If you are looking for a nice hike that isn't strenuous I would suggest the Valley Loop Trail in Yosemite Valley. The trail hugs the edge of the valley will take you by Mirror Lake, Yosemite Falls and El Capitan. If you do the full loop it is about 11.5 miles. The good thing is if you want to stop at any time you are close to a bus stop and you can return any time. On this hike we had 2 small children so we ended up hiking about 8 miles total. We left the trail between Yosemite Falls and El Capitan and traversed a meadow to cross the swinging bridge to get back to our campsite. The meadow is beautiful and  is now one of my favorite sites as seen in the picture above.

One other benefit is there are places along the way like Yosemite Lodge and Half Dome Village where you can take a break.