I took my two year old to Disney (well, my mom was there, but she was at a convention, so it was me and boy till around 6pm). It's tough but do-able. I did depend on the kindness of strangers most of the time! Dads with families often helped me get my stroller on the buses (I never asked, I guess the guys just recognized my "mom alone" face!), I was also the first one/first off with buses too! I guess lots of people figured that I was the tougher one to get out, or maybe the just wanted me off the bus quickly? I NEVER asked for the kindness. If your kiddo is a runner, get a leash (I know, touchy subject!). But it helped when boy wanted to walk and I didn't want to drop everything in the middle of main street to chase after him. Meals are challenging, esp quick service when you are trying to navigate a crowded place and get a table, drinks and food all without spilling stuff on the kid. But CMs were super sweet - esp at Animal Kingdom. I had one CM who found a table, high chair, carried my food and got me a drink! Didn't ask (but you can ask them, they are sweet), but again - the mom face helps.
Don't forget about the baby care centers. We took advantage of them. The nurses and CMs who staff those areas are all sympathetic and good with kids. Would I do it again? Yeah. We are locals, so sometimes we just drop down to Port Orleans just to get gumbo or go to the parks by ourselves in general. Just have a bit of a strategy, and have a sense of humor about stuff. You will be good.