I just called the Vistana to get some info for you. They offer a shuttle which is $8 pp, children under 3 are free. Also*** They do not provide transportation after noon.(12) So you could not park hop with this**
I would not depend on just their transportation! We usually rent through Alamo, (tend to have the lowest prices) if you are a member of BJ,s, costco, etc. they have a pamphlet out in their stores with discount codes. Usually about 20-25% off plus either a free day, or upgrade, etc. We were there in Sept/Oct and paid $138 for a midsize for a week. Also, you can check
AAA, or Walmart.com under travel section. Also, you may want to go to a store where there is a kitchen at your hotel, downtown disney or other places. It is very easy to navigate around there.
As for park hopping.... Disney offers extra magic hours for guests that stay at their hotels. ex. Magic Kingdom may have an A.M. early entry... (very busy) and at night they may have say regular park hours until 7pm, then extra magic hours(if staying on site) from 7-10p. (usually 3pm and very busy again).
When we went and stayed at the Vistana we found out which parks were offering the extra magic hours that day and avoided it like the plague!!
As for what to request: If you want something newer but smaller I'd request Cascades & can't remember the other newer one. We have also stayed in the Fountains and found those to be nice,(not as updated, but not bad). Comparing the units we had the Fountains was quite a bit bigger :teeth