I didnt know id be trapped out here before i could finish the last gym but it there any way to go back after i took a trip out to the 1st island?

Yeah, just go to Vermillion and where the S.S Anne was, is now where the boat to the Sevii Islands is

I think he was asking how to get back to Vermillion, because he was talking about Gyms and there aren't any on the Sevii Islands.

If your after the Gym where you beat Blaine, you gotta help out Celio on the Islands by going to 2 Island talking to the man in the game corner, and then saving his daughter in Berry Forest on 3 Island. Then you give him some kind of rock and you get a moon stone for your troubles. Then go talk to Bill and Celio and Bill will say he's ready to leave and then you can go back to the mainland, and you can go back whenever you want using the boat where the SS Anne was at.

psychicFTW is right, and you cant return to kanto untill you've helped cello.