Don't worry! If there is any place on earth you can do solo, basically never mind which physical disability, it's WDW. Very accessible, no unneeded regulation, simply do whatever you want and can do. One thing I did learn from my first solo trip; have a back up 'what in case.....' plan. Sure enough, I had all kinds of problems on that first solo trip which basically left me stranded at the room. Didn't think about that, so was in a bit of a jam. The resort CM's helped me out great and I had a blast, but it did teach me a lesson.
Since then I always travel with some 'what in case......' plans and info for my chairs. If something breaks or dies on me, I know what to do and whom to contact. Did still have to learn that lesson regarding medical stuff, but another trip took care of that so to say.

Really though, it's very easy. You'll have a blast!
Have you already put everything in place for airport assistance should you need it? MCO can be a bit stretched out, esp. if you want to pick up your luggage yourself before checking into DME (I do, since they no longer sent out the yellow tags to those of us not from the US. Main reason; I DO NOT want to hand anybody else my luggage stubs as some of them will correspond to my chairs. Sometimes things get messed up at check in and different stubs correspond with the luggage and chairs than they tell you. If any damage or problems do occur with the aids and/or medical stuff, I want all of the stubs in my own control not with the CM's working the DME desk)
Another pretty major difference if you do decide to use airport assistance; apparently these are tipping positions within the US unlike within the EU. While opinions vary a bit on this subject amongst those in the US themselves, if you run into the 'wrong' person providing the assistance they will let you 'know' this.

