The following thread is still useful although not completely updated: Ladyboy Friendly Hotels
Most hotels located near the red light areas (Nana Plaza, Patpong, Soi Cowboy), are guest friendly - that is they will allow you one visitor at a time to your room. If you try for two though, they may charge you extra. It is also common practice for the front desk to ask for the ID of your guest - which is actually a good thing as you have some way to track her down in case something untoward happens. They will usually return it to her, after they confirm you are ok, when she leaves. If you are not ok, they keep her ID.
There are some recent posts in the trip reports and holiday snaps I would suggest you read. A few forum members have tried social medial such as LIne, Whatsapp and Thai Friendly with some success as well.