I'm getting in this conversation a little late.
Will try to answer some questions that haven't already been addressed.
Cascades and Lakes are two newest sections. Both provide elevators and zero entry pools which make it very easy for little ones, elderly and those with disabilities. Even though the Cascades is the newest and very beautifully decorated, I prefer the Lakes because the units are a tad larger. Particularily noticeable in the living/dining room area. Felt a little more cramped in the Cascades, especially if you have any more than 4-5 people staying.
The Fountains I and II are midway between the old and the new. I own here so I can answer specific questions about this section. I prefer the Fountains II because it's slightly newer and has the jacuzzi in the master bedroom (like the Cascades and Lakes) vs the tub in the master bathroom as in all the other sections. There are several Fountains II units that do NOT have a water view though......so I'll take a Fountains I over a Fountains II if it means sacrificing the water view in II.
The older units are generally clean but you could notice some outdated decor. The last time we stayed in an older unit it was the Spas. This was the end of 1999. Felt like a blast out of the 1980's decor. We weren't too thrilled with it when we compared it to our Fountains units. The carpet in the hallways was slightly torn, some tile missing in the hall bathroom, ceiling fan in the second bedroom was very wobbly (we reported all this to the resort). Regular maintenance is performed on all the sections of the resort so hopefully some of these things were attended to. On the positive side, this older Spas unit has brand new, shiny kitchen appliances. Felt like we were the first to use them. All sections (besides Cascades and Lakes) have only stairs to get to your villa. So if being on a 2nd or 3rd floor will be a problem with a family member, you'll need to request "ground floor" or "elevator building" for medical reasons. The Falls sections, though one of the older ones, does have a fun pool slide (only slide onsite). I'd only recommend this slide for kids 4-5 or older though. It's pretty quick and an enclosed tube. The Courts is the oldest section and set up more like townhomes. It actually was a condo development that existed prior to Vistana purchasing the land. There are no water views in this section. A poster on the DIS stayed there fairly recently and had snapped some great pics that showed so improvements/upgrades made to this area. For the life of me I cannot find the pics, but I recall it made me feel not so nervous about ever staying here.
The Cascades, Springs, Palms, Spas & Courts are in the slightly more bustling area of the resort that is closer to the General Store and Zimmies restaurant. You'll literally need to drive out of this area, through a second guard gate, to get to the Lakes and Fountains sections. Over there, which I find a quieter more low-key section, you will find the Flamingo Cafe restaurant. There are children's playgrounds scattered throughout the resort.
As for what to bring.....dishwasher detergent and dishwashing liquid soap are provided. Even though you can get towels at the pools, you need to sign them in and out or you will be charged for them. So we prefer to bring our own towels---and we prefer our longer beach towel versions. But if you're absolutely looking for a way to condense packing, then the Vistana-provided towels are fine. Bring your own shampoo/conditioner (bath soap is provided). If you feel you need to replenish any items during your stay, just push the housekeeping button on the phone. They will bring up extra items, free of charge, we just choose to tip them. Yes, there are hairdryers---the wall mounted kind. Not very powerful drying capacity, but adequate.
I have some pics at my sonyimagestation storage site if you'd like to see some of the different units :
http://www.imagestation.com/album/pictures.html?id=4287948459
I believe the site may require you to "register" in order to view the pics. The registration is free.
Let me know if I can help any further.