If your aim is to hike to Rogers Pass Lake and Heart Lake, follow the South Boulder Trail all the way. Combined, it's about 9 miles round trip from the trailhead to the two lakes. But due to greater elevation gain, this hike is a bit more strenuous than Crater or Forest Lakes.
ROGERS PASS LAKE (Elevation 11,028 feet) - 9 miles
This is a beautiful hike as well; there are streams and amazing meadows of wildflowers along the trail, especially up by the lakes. See photo below.
Hiking here in autumn is also great. There will be very few wildflowers but most of the foliage will be transformed from green to red, yellow and orange - a different view of the landscape altogether. You might get lucky to find marmots if you stay a while. They are shy animals, which is good.
PREVIOUS... CRATER LAKES
If you are camping, you will have time to go hiking to the top of the Continental Divide, which separates the Pacific and Atlantic watersheds.
There are many fine campsites in the James Peak Wilderness, but campfires are not allowed and group size is limited to only 12 - including pets.