Among the lakes around June lake loop, grant Lake is least favorite one even it is the largest one (over 1100 acres). It is partly because there is almost no trees around the shore, and partly because there is not much facility around the lake either (except Grant Lake Marina). But I think this lake is as good as June Lake, or Silver Lake, if not better
There are many place where you can drive directly to the banks of the lake, which is much more accessible than other lakes around the loop. The water is super clean. In the summer, you can swim, sunbath, or fishing here. There is no crowd around its eight mile shoreline. You can easily find a quiet place and enjoy the whole day by yourself.
Even better, there is no mosquito around this lake. By comparison, you will certainly collect a bunch of mosquito bites around the other lakes along the loop. If you have a boat or SUP, it is much easier to launch from Grant lake than other places.
The marina itself is a full service place. It has everything you needs: snacks, gas, boat rental, and tackle. The service people are super friendly. Couple of camp grounds with shower are located nearby too.
Do not forget sun screen cream, there is no shade on the shore, and you can easily get sun burns. Most the roads to the shore are unpaved, so be sure to drive slowly, otherwise you may be at the risk of getting a flat tire.