Hi @Kelsey C.
I have a short term rental in Clermont, just outside Kissimmee and 10 miles from the Disney Main Gate. Now in the third year with this property. Vacancy rate is hard to determine, and for us has varied greatly. The Orlando/Disney area is flooded with short term rentals, and this market is in direct competition with the Disney resorts, since many feel the advantages of staying on Disney property outweighs the disadvantages of staying in a hotel. Plus many do not even know that you can rent a whole house with a pool for the same price as a nice hotel. So unfortunately the supply and demand is offset.
I think that you can minimize vacancy by being really active in marketing the property, increasing the amount of advertising funds you are willing to spend, and responding to inquiries quickly. Also by decorating nicely and providing new electronics and other perks, you can appeal to more people and you can ask for a higher rate and probably get better guests. But all of this takes lots of time and money. And the operating expenses are always more than you expect them to be.
You can usually depend on booking nights during the "Peak" seasons the most. Those are Spring Break, Summer (middle of June through middle of August), and holiday weeks like Thanksgiving, Christmas and New Years. Although there is no guarantee and not every day during those times will be booked.
This year has not been very good for us. We hope it turns around. We think this is due in part by big changes made by our vacation rental listing company.
Our local long-term rental investment properties out-perform our FL short term rental right now, but the income we do get from it does help to offset the costs when we want to use it personally.
Hope this helps a little!