Some good lake/wildflower hikes I've done in/around Summit (I can't vouch for how the wildflowers are right now though):Herman Lake:
(exit 218) - easy 6-7 miles roundtrip - one of my favorites, with lots of wildflowers, ending at Herman Lake. Eccles Pass:
(off the eastern Frisco exit roundabout) - 10 miles roundtrip - the first mile or two is the hardest but then it mellows out onto an alpine meadow thick with wildflowers. Doesn't end at a lake, but the view from Eccles Pass is stunning. Loveland Pass East Ridge:
- once you gain the ridgeline, there are lots of tiny wildflowers all over, and the view is spectacular to boot. Mayflower Gulch:
(off Highway 91, about 6 miles south of Copper) - not a lake hike, but profusion of wildflowers in the valley. Guanella Pass:
a little far from Summit, but the hike to Square Top Lakes (away from Grays and Torreys) provides great wildflowers and two nice lakes.
PM me if you'd like more info on any of these hikes.