Vail in the summer

Colorado white water is better than anything in Tennessee

Vail has an adventure ridge (modern and new)on top the mountain if you have kids that's fun - they have jeep tours, tubing, ropes course, alpine slide, zipline, etc.

Buena Vista(pronounced Buyna Vista, don't ask me) is where you want to start your rafting trip. If we don't get more snow there won't be a rafting season here. If you head down that way I think Cottonwood pass is opening back up this year after getting the west side paved. You'll also pass up Independence Pass on the way there. Highly recommend both.

If you man bike get a shuttle or big boy it up to the top of the pass and take Bowmans over to Two Elks. Two Elks will spit you out in Minturn where you can add in Meadow Man to Avon. One of my favorite if not my favorite trail in Colorado. In peak season the wildflowers are better than Crested Butte's. Plenty of good trails in Eagle also if biking is your thing.

For trails on the mountain with lift assist Radio Flyer is the goods. You could also take Grand Traverse over to Two Elks, Grand Traverse does exactly what the name implies.

Cant think of any waterfall hikes in Vail, I could be wrong though. You could hike Elbert one day. It is long but really just a steep walk with no bouldering or scrambling.

Coming from sea level you should be in pretty good shape to do anything I recommended except for maybe the rafting.

Hanging Lake is about 45 minutes away, get there early to beat the crowds

Get a Hyatt Chase card just to get two nights free. $800 value at Park Hyatt Beaver Creek.