I am mostly into women but definitely plan on being with a TS at least once. Can any of you tell me if the TS providers in general allow you to enter their backdoor or not? Do they charge a lot more for them to let you do that?

First know what you'd like to try. Then look for a provider in your area that appeals to you. THEN FIND SOME REVIEWS.if no reviews then ask questions when you contact . if you like kissing do they? are they full service? most will not really respond to specific questions of service but i have found that most will tell if they are top or bottom. most ts providers can be a great sexual experience so enjoy .

I would think that a top-tops you.  They fuck you in the ass.
I would think that a bottom-is on bottom for you.  You fuck them in the ass.