Great choice. I did Kearsarge Pass as a warm up the day before I climbed Whitney for the first time, and stayed at Onion Valley before heading to Lone Pine and the Portal to start our trek. Worked out perfectly.
The campground in OV is nice enough, though you may hear the campground host banging pots around during the middle of the night in an effort to scare off bears. You can also climb up a bit and camp at one of the lakes..... Good fishing sometimes.....
