I want to add another vote for Massachusetts. I'm biased: I came here for grad school many years ago and never left. I recommend more the areas outside or within driving distance of Boston, though. (Sorry P'town!) There are rural areas which are gorgeous, and post-industrial cities which are more affordable...but many of those places don't have easy access to trans-related health care, if that's a factor. Yes, even Cape Cod, although that area's getting better.
Eastern MA can be pricey as far as housing. On the other hand, the public transportation system is quite good. We have a shiny new statewide employment, housing, and credit access trans rights law. We're still working on public accommodations, but many venues are already good on that account either because of more local laws or things like Title IX jurisdiction. We have same sex marriage, allowing for the widest variety of [dyadic] marriage configurations

and a driver's license gender policy that goes by lived gender regardless of surgery or birth certificate marker. Our health care system (the model for the Affordable Care Act) means that even unemployed and under-employed residents are able to be insured by MassHealth, Commonwealth Care, etc. While trans care is technically excluded, many (most?) trans people accessing the free or low cost options find that basic care, hormones, and bloodwork are covered. Some trans health care providers work under informed consent models. We have an active network of trans advocacy organizations, led by
MassTPC.org, and for those who wish it, a hoppin' public trans and gender queer subculture (not just in Boston, but also in western MA).
There are real gaps, for sure - like for some reason peer support groups for trans women are lacking? Jobs can be tough to get, although more and more employers are covering trans health including surgery in health insurance plans. And there are areas of the state where if you are broke and don't have a car, it's going to be difficult to access services.
Finally: most pertinent to your situation, tooling around in your RV: the parking sucks.