Cats are very adaptable! I'd take him along. When you get to the new place you should plan on keeping him inside for a few days to let him get used to the new digs. Just because he has been an outdoor cat doesn't mean he couldn't become an indoor one. I'm a big proponent of not letting cats roam. If you do let him out, I'd do it in small doses and keep tabs on him so he doesn't get confused or lost. If you take him with you, plan on taking full ownership too....shots, tags, the whole thing. It sounds like you've pretty much adopted him already. :)