DopeyDave,
We've only stayed at the Treehouse villas once, this past July, but here are my thoughts. Our 1st day at the resort we basically hiked along the connecting path through the woods to SSR, which wasn't a bad walk, but in the humidity it was rough. So then we started to catch the bus. Busing times from THV to the Hospitality area was decent, but then it's the last pickup in the resort so by the time the bus gets to this stop early in the morning a lot of the busses are filled. Then after a long day at the park you basically repeat the process. Park back to SSR Hospitality House, exit bus, then wait for the THV bus, and when you are waiting for a bus after midnight on a long day at the park it seemed like it took forever to come. What we discovered that worked 100 times better in my opinion, unfortunately it was our last 2 days, was to drive our car from our THV into SSR and then make an immediate right and park near that bus stop, which happens to be the 1st stop in the resort. So we were able to easily get a seat, and then after a long day we got off at the 1st stop and BAM there was our car and we were promptly on our way back to THV.
Since there are 6 of us driving is our only affordable option to get to WDW from Ohio so we really like the Disney Busing as nothing is better than Free, but these past few years we've been using the buses less and less, unless we are going to Magic Kingdom. It is a lot faster and you get free parking at the Parks so we usually just drive to all the parks except MK. Nothing beats getting dropped off or picked up right outside the gates.
Sorry for the tangent there, but I hope that helps you out with our busing experience at THV. We loved the area, but driving to that 1st bus stop really was the way to go!!