Hey Curtis,
I did Whitney last year solo. Well, kinda solo. I met two guys on the trail who obviously hiked at the same pace as me, so we ended up hiking together for much of the two days we were on the trail.

I like the three day plan that you have. Last year the first day was great...a pleasant hike to Trail Camp with plenty of time to catch the beautiful scenery. The second day I went to the summit and then all the way back down to the portal. This is totally doable, but it really is a grind and you don't get to enjoy the hike down as much. Spending that extra night at trail camp is a great idea.
td