The rest room often comes up here on Susan's, and no doubt it will continue to come up as long as there are members here on this board. My own opinion is that no matter if you are here and identify as TS/CD/TV, Post-op it's a matter of passing in the general public. If you pass without any problems then there are no problems; go for it, no one will be any the wiser, but as I've said before, do so at your own peril. Additionally, being Post-op doesn't guarantee you won't encounter problems as there are those who even being post op still have some difficulty passing in an enclosed environment such as the washroom.
For the general public their situation is simple; men use the mens room and women use the women's room, plain and simple. I think it would be safe to say that many feel this way about gendered washrooms, no matter what rights have been bestowed on the TG community, and they are going to continue to think this way until the general public changes their opinion, their social upbringing, their moral beliefs etc. and this is something legislation can't do.
Even if you are granted the right to use the washroom of the gender you present as, or identify with, we do ourselves no good by entering such places if we don't pass. We constantly push out need for our rights and freedoms, but at the same time we need to consider others who we wish to share our lives with.
I know that this may sound harsh but if you don't pass then stay out.