The Alabama Hills Cafe is great! Love their food and the people are friendly :-)
If my son and I ever do Whitney again, we'll spend a night at Trail Camp as well. Going from Portal to summit to Portal in a day was a tough day.
For us, the last mile of trail and 600 feet of elevation to the summit felt like it took forever. Lone Pine Lake to the trailhead was a blur as we motored back down.
Congrats on doing it with your family!