You could start with that list that HRC puts together about best LGBT workplaces. While they may not explicitly mention anything about trans people on their websites, by and large they'll have policies in place already which would work to your advantage. I applied to two places from those lists and while their gender selection was only male/female, they did let me put in a preferred name. The recruiters did not use it when they contacted me though. Seems to be pretty hit or miss.
As to the rest of your question, I work in hospitality consulting in Washington DC. No one at my company has ever wanted health insurance before, so part of my job currently is making that happen. As of right now I'm only partially out at work, but I don't anticipate any issues.
I also do some online work (maybe 10 hours per week) that has thus far covered all of my transition expenses (doctor's visits, testosterone, therapy, etc.).
Ultimately it's going to depend where you live and what the job market is like there. Big cities tend to have more opportunities, but you have to have the right skill set for a lot of things.
