FYI, I'm not sure that the person you're responding to knows what they're talking about. You wouldn't want to "hike around the lake". It's 30 to 40 miles and is a busy road. Circumnavigation only makes sense in the winter when the roads are closed, and it's very difficult.

The hikes in the park in the summer are primarily up peaks along the rim, although the PCT goes by too. Iv'e gone up Garfield and Watchman in the winter, but not the summer so I can't really advise there.

Good luck!