We took Quest for the West last summer. I don't know what you would consider strenuous, so I'll give a brief description of what I remember.
In Jackson Hole we walked two blocks (flat ground) from the Wort Hotel to the historic theater for lunch and entertainment, and then walked back.
Next was river rafting. You have your choice of white water rafting or a more leisurely float on a flatter section of river. We took the white water rafting so I can't comment on the float. For the white water rafting we had to walk from the bus down a boat launch ramp (approx. 40 yards) to the raft. There were 4-5 sections of rapids where the folks on the outside of the raft were expected to paddle pretty vigorously. When we stopped there was a climb out of the river area to the bus which was the equivalent of climbing five flights of stairs.
The rest of Jackson Hole included going out to dinner on our own, browsing the stores, and walking across the town green to see a mock western shoot-out.
After leaving Jackson Hole, you stop at the Grand Teton National Park visitor center (get off the bus, walk around the center/exhibits, walk back to the bus). Then stop at a small lake for a picnic lunch (again, get off the bus, walk 40 yds to the lake/picnic tables, get back on the bus). Then make a longer stop at Jenny Lake. Here you walk 100 yds or so down a slight incline to the boat dock, where you take a shuttle/ferry boat across the lake to a dock on the other side. From here there is a moderately demanding trail hike to the hidden falls. The total distance is approx. one mile in and another back, climbing about 500 feet in elevation. There a lots of chances to stop, rest, and take pictures. One CM leads and the other always stays at the back never leaving anyone behind. (I know this because I was always bringing up the rear due to my stopping for photo opportunities.) At the end of the hike is a group picture and a boat ride back across the lake. After you disembark the boat there is time to visit park ranger's center and the gift shop.
Before the bus reaches the hotel, there is a stop at Yellowstone's West Geyser Basin. You get off the bus and the CMs give a tour of the area. Here you are walking on basically flat ground on the wooden boardwalks. You can walk as much or as little as you like.
To be continued...