They shouldn't have too much of a problem getting a ride to Independance. From Indy to Lone Pine may be a problem.
In the last 5 weeks I have been up to Onion Valley and Horseshoe Meadows several times and have given more that 20 PCT hikers rides to town, and to Bishop. It's hard to say no.
You could call one of the shuttle services if you are certain of their exit date and time.
Paul
