1. Where would you stay ($50 - $75/night range if possible).......$50-75 will be tough and impossible in high season (even $100 is low in high season, June-September). No chance inside the park. Check out www.yellowstonerivermotel.com
2. What waters would you fish - Same waters every day or hit a variety? Any lakes?.......Definitely fish a variety. That's really the whole point of this area. Bigger fish, better fish of certain species, etc. are all available elsewhere, but not the variety in such a small area. Except Hebgen, lakes are usually an early and late season bet unless you're going high in elevation.
3. What time of year would be best to go? ------------ Depends on if you can hike or not. If yes, this year, late July. That's when the widest range of waters are fishing well, so even though there's a lot of people, there's more room to spread out, too. If you'd rather stay relatively close to the road, October. September is typically quite busy now until at least the 20th, and with the likely low-normal water levels this year, they will be super-spooky on roadside streams. Prior to the usual equinox storm around the 20th, early-mid September is my least favorite time to guide in the region. I have very in-depth info on flies, hatches, river guides, etc. here: http://parksflyshop.com/howto/planning/planning.html
4. The budget can only handle a guided trip for one day, guide recommendations and waters: --------------Well, hopefully me or at least someone from my shop. If July, I'd suggest a float on the Yellowstone. If October, either a private lake trip or hunting runner browns on foot in the park.
5. Should we bring the pontoon boats? --------------- Depends on how much whitewater they can handle, how good you are with them, and when you want to come. In July, I'd say no because the Yellowstone is burly enough that it would be hard to control the boats and fish, and there aren't many places to bank fish, and there's really no reason to fish roadside lakes at that time because the streams are so good. In the fall, yes, though bear in mind you can't use them on flowing water inside the park. Rivers are much lower in the fall and there are a lot more places to get out and fish the riffle corners.


Hope that helps.