For those visiting Central Florida, we recommend renting a car which we believe will make your stay much more enjoyable.
International Drive Realty Orlando
P.S. - If you are looking for service in the tourist area, there is also the I-Ride Trolley which operates in Orlando along much of International Drive (as far south as the Premium Outlets) and Universal Boulevard. There are stops near many of our popular attractions. http://www.iridetrolley.com
Although there is a Lynx bus service, it doesn't meet everyone's needs - for example, I have a home in the 34747 zip code which is west Kissimmee according to the US Postal Service, but in practical terms I could not live in that house without having the use of my own car.
You may get some help by looking at htttp://trip1.golynx.com/ and put in a few addresses to see how well served is the part of Kissimmee you're interested in. If you're still looking for a property or you need more guidance, Realtors and others on here will be pleased to give you more input on request.