Transsexual
Go to the Reviews section here on TER and start browsing.
To help avoid reading a fake review, be sure to check out the other reviews of the reviewer. No guarantee here--there are some pathological liars out there.
Be wary of craigslist (CL); it's a hit or miss, and you'd like to avoid TOFTT (taking one for the team). Even so, there are some terrific girls on CL.
Do relax and be totally honest with yourself and the girl.
Do clean up your body before your visit. Please!
Using your own cell phone isn't the safest way to go, but it's not necessarily a bad thing. A quality girl won't abuse it. Again, do the research in the TER reviews.
The 2-call is very common. Call 1: make the appointment. Call 2: you've arrived at the location--she'll tell ya where to go.
Don't expect a long phone conversation--they're busy, too. Think about what you want to say--be polite, be honest. No dirty talk.
Do say it's your first time and that you may need to talk all the while during the visit.
As I am still quite new to this as well, I pay a lot of attention to her tone of voice. Talking with India is like a walk in paradise--she's so good at creating comfort and relaxation. On the other hand, there are some that can't seem to carry even a brief conversation (maybe they've had a bad week; you really don't know).
One thing that I think is very cool about Lee Taylor in Chicago is that she tries to connect with her clients. She's on my "to see" list!
You also need to ask yourself--are you there for the experience of it all or just to watch her cum? Some guys are cum-watchers, and they really don't have a realistic understanding of the TS World. If she advertises as a Top, it's more likely she can get it up. But, cum? This is NOT a given. After all, let's see you take hormones and have 5-6 orgasms in a day! 
Be accommodating. Drop the expectations--let the experience flow. Be glad to see her!
The best quality girls state their donation and that's all it is. If they want more money, that's called "upselling," and it's VERY unprofessional. If they start changing the price, I'd leave.
FYI: Most providers won't do long-range date planning; it's just too fluid of a situation. Trying to contact them is o.k., I guess, but don't expect too much in return.
You need to decide what you want and when you want it--that's when the girls prefer your call.
I feel for your situation because I, too, had a nerve-racking first time. My first inclination was wanting to talk with the provider ahead of time at length, but that's just not likely to happen.
It's great that you get to travel to so many cities, but then, I guess that makes your research that much tougher. Since you have more options than most of us (city-by-city), go with a well-reviewed gal for your first time--don't take a chance on CL.
Of course, be sure to report back! Have fun!