Re: I am 26, and seriously considering moving aboard with my girlfriend. Any advice?
You're able to get a $100,000 loan for a sailboat made in the 90s and they're okay with you living on it? Wow. I think your hardest part of the plan is over.
A slip for a longer boat, and liveaboard fees, and maintenance & repairs, and if your significant-other will require a storage facility for off-season clothes, those are all costs that take a fair sized dent out of whatever income you have.
It's very rewarding though, if you can work it all out. I'd suggest buying a well-known boat whose manufacturer is still in business (Catalina, benetaeu, etc)
1985 Catalina 30 Std Rig "A Cenoura"