I've recruited EVERY legendary in RRT except for Celebi and Jirachi (the start at lvl 1 I hate those!) But here's advice on all the others:
(BTW I did this all with my own character, a lvl 70+ Charizard at first, now lvl 100)
Articuno, Zapdos, and Moltres
As you learned from your fugitive journey, you know where the birds lie. When you recruit them you automatically get their Friend Area, Legendary island. Chance of joining is Very Likely, but there are directions.
:You must not take any missions. This is the case for any 2-part dungeon.
:You must recruit them in the following order: Articuno, Moltres, Zapdos.
:Because their size is 4, you can only recruit 1 extra -or no extra if you are Metagross etc. But you can always send friends back at the midway point.
Articuno I believe is the strongest because of Powder Snow - I have mine almost at lvl 90 just by going to the dojo - and recruiting them all unlocks the Lugia event, which I will discuss next:
Getting the birds may have been easy but this sure won't be. First you need HM Surf and a Water Pokemon to enter. For this first time around, I brought myself (charizard), my faithful companion (sceptile) and Poliwrath (who I promptly sent back). Floors 15, 35, 55 and 75 are one room monster houses, so Heat Wave or another widespread attack is great. I recommend just attacking once then head for the stairs.
Lugia waits for you on B99F. As with the other birds, you can only have 1 extra because of size. Chance of join is very likely, and he has about 800 HP. Lugia joins you at lvl 30, and Deep-Sea Current is automatically added.
You will take on Raikou, Entei, and Suicune as part of the Mirage Pokemon Quest. They wait on 30F of their respective lairs, the 29F having evolution stones: Entei -Fire, Raikou -Thunder, Suicune -Water. Chance of join is Unlikely, but you can't recruit 'em first time around. Purchase their Friend Area, Sacred Field, from Wigglytuff for 6500 poke, then come back with the Friend Bow you get from Mount Faraway. You may have to clear the dungeon several times. the dogs have about 650 HP, and I had to recruit them the 5th time around. Keep trying, my friends.
Ho-Oh is the culmination of the Mirage Pokemon Quest. He waits at 40F and is incredibly tough if you come unprepared (my lvl 90 pp-less charizard lost later on!), so come with Max Elixirs and Huge Apples. His friend area, Rainbow Peak must be purchased for 6500 poke. Also bring a key for the locked door on 30F. Inside is one of the greatest items in Rescue Team - the Friend Bow, increasing % of recruit chance. When you get to 40F, go all out - this will be no walk in the park!
Also, all 4 dungeons of the Mirage Quest are quicksavers and require Surf.
The beasts join at lvl 45, Ho-Oh at lvl 50.
Meteor Cave is a sinister 20 floor dungeon unlocked after beating Lugia. Inside lurks Deoxys, ready to join if your level is really high ( I had to wait until I was lvl 100). But you have to go alone in there, with only 3 items in the bag + 1 hold item. The only items in there are money, and you must find and defeat Deoxys's mirage to climb down the stairs. I advise you do this: Take your strongest guy and bring 2 Huge Apples and a Reviver Seed, and have him hold X-Ray Specs, otherwise you could be stuck on one floor forever! (Rescue missions are irritating too, as there's water in there and I had to rescue a Seel! good for me charizard was an all-terrain hiker...). Deoxys has about 800 Hp (i think), and joins you at lvl 35. His friend area, Enclosed island, is auto-added.
Western Cave is the best source of keys in the game. Also on B59F the item Beauty Scarf to evolve Feebas is here. There isn't much food and the underlings are stronger than other underlings. Bring Huge Apples - there's no food lying around. But there are reviver seeds about so that's a plus. Floors B50F thru B60F are Sandstorm floors almost always so get through those quick. Mewtwo awaits on B99F, and he shouldn't be too hard. his hp is about 800, but you'll have to come back to get him, also when you buy Cryptic Cave (6500poke). Mewtwo is a good pokemon for the lvl 1 start dungeons because his lvl rate as well as Mew's is very fast.
Latios and Latias:
When you buy the Southern Island area for 9000poke (whoa), this leg of the story begins. Kecleon shop has been raided in the night by someone. They believe the thief headed to Northern Range. Set out to bring him to justice. Northern Range is an easy 25 floor dungeon, with Latios at 25F. Defeat him to get to Part 2 of this quest. Latios will be taken back to Pokemon Square, where he will explain his motives - Latias his sister has fallen into Pitfall Valley so he stole the TMs in an effort to rescue her. you gladly agree (I assume) to take over the effort. Pitfall Valley has many rare pokemon like Aerodactyl here. It is 24 floors long and then Latias appears on B25F (although this is technically part of the dungeon). You help Latias back, and a happy reunion ensues. Latios wishes to repay you by joining the team. DO IT OR ELSE THIS IS YOUR ONLY OPPORTUNITY. Latias is lvl 28 and Latios is lvl 30.
I think Sky tower summit is just as sinister as Meteor Cave. The same rules apply for the birds as do him. Sky Tower Summit has 8 floors plus Rayquaza but the stairs are hard to find. Conserve your Huge Apples for the Summit and if your belly empties, bring oran berries or a Pokemon with Giga Drain. Chance of join is Very Unlikely, so save at the midway point and if he doesn't join, turn off and start from the middle again. Also, Stratos Lookout (friend area) is an auto add (he joins at lvl 45), and this dungeon requires fly to enter.
Stormy Sea is just a milder version of Silver Trench. You still need Dive, however if you are a Fire Pokemon don't go in until you're at least lvl 50. I had that problem so to be safe, I brought along good ol' Sceptile and Magneton (
) . Unfortunately because of size Kyogre can't join you like that. Kyogre waits on B40F and considering, he's not that hard to beat. He has about 600HP I believe, he joins at lvl 25 (low), and friend area Seafloor Cave is an auto-add.
This is just an easier version of Rayquaza's. Even though Magma Cavern Pit has 3 floors, in reality it's just 1 then Groudon. Chance is Very Unlikely so keep trying (for both Groudon and Rayquaza i had to try 9 times!). Volcanic Pit friend area is an auto-add. Groudon is lvl 40 or 45 (i forgot...)
The Regis and Mew:
That's not a dungeon, that's a nightmare! Buried Relic may be 99 floors but it has the most traps of all dungeons - every trap in the game is there, not to mention 4 legendaries and 4 HMs -Rock Smash on B45F, Flash on B50F, Strength on B60F and Cut on B80F.
i will discuss items behind doors in another post.
The Trap seer IQ skill will be excellent. The legendaries won't join you first time round, and their odds are Unlikely. But, that's what the Friend Bow's for... On B15F, you fight Regirock. All Regis have about 500hp. defeat him for the Rock Part. You must also fight on B25F against Regice, and B35 against Registeel, gathering their parts. They will combine to form the Music Box which makes Mew appear. For now finish the dungeon - which is still hard! To recruit the Regis buy Ancient Relic friend area (6500poke) and bring the Music box or the relevant part in your inventory. When you get one play safe and use an escape orb. There is little chance that a lvl 25 pokemon will survive 70+ trap rigged floors. There's no telling when Mew will appear (anywhere between B36F and B98F) but just perservere. You may have to go through the nightmare several times (I went thru 5 times before I got all 4 on 4 different visits all on last Friday night!!) Mew needs the area Final Island bought (8500poke) and joins at lvl 40, as does Mewtwo. The Regis join at lvls 18 (rock), 23 (ice) and 25 (steel).
Celebi and Jirachi:
I haven't done this for myself yet. But, here are some suggestions about dos and don'ts:
:don't bring a pokemon that needs 300 exp for the first lvl-up. That makes everything cumbersome.
ass Scarves are good. They shrug off most attacks, but you'll need Huge Apples for the best effect.
:One person suggested a Kingdra/Kyogre/Frustration strategy. I haven't tried this but it sounds good!
Mew: Even though Mewtwo and Mew both level up fast, Mew gets a better stat gain rate. also he can learn anything.
Registeel: This may sound weird, but trust me I got to Purity forest 33F with a Pass Scarf before a Poliwag killed me. The reasoning is simple: first, as a Steel type he can't get poisoned, trap or otherwise. second, with Explosion as a starting move he can deal 80 damage to anyone two squares away at the cost of half his HP. This is an AWESOME way to get rid of a monster house. Having him taught Rest also helps to gain health.
well that's all for now; so long...