Sandi, did/do you know there are 2 types of accessible rooms? The first is with grabbars, raised toilet seat and with a tub. You can ask for a showerseat, so you can sit down during showering.
If you can not handle that, than the second type is as above, but with a rollin shower. In that setting you can roll the wheelchair right up to the shower, transfer onto the showerseat, move the wheelchair back a bit, close the shower curtain, shower, and transfer back into the wheelchair.
The difference really lies within the shower and the question if it is safe for you to transfer into a tub (with or without showerseat), or you'll need more than that.
If you do think you need a rollin shower; call back. You need to ask for such a thing very specifically. Only asking for an accessible room normally gets you the first type of room (with tub). You are correct with there being 99 accessible rooms at CSR, which is a total of both types combined. (so even less rooms for those that need a roll in shower).
Another subject; how used are you to wheeling around? The parks tend to eat up a lot of miles per day, which can be exhausting enough for those who are used to wheeling around fulltime. I don't know if you've looked into it already, but there are also some hidden challenges at The World. For instance; MK slowly goes uphill. Or the cobblestones at AK (ouch) etc.
If you're not used to doing multiple miles yet, have a back up plan. Look into renting an
ECV if you'ld end up needing one. The same goes if you're considering having somebody push you. For them it can also be hard work, caused by the miles, weather etc.
If you haven't read them yet; read the stickies on top of the disABILITIES. They are full of great info about WDW and the resorts with a special need. There also is great info on here about all kinds of rides, waitlines etc. so you know what you could expect and act accordingly so you get the best possible experience.