Thats a great trip. Not to long, not to short. The view when you pop out on top of Kearsarge Pass is just the begining.
A couple of things to consider here in regards to "Meeting a friend for the last leg"
a. easy meeting place at Charlotte Lake (about 8mi from OV)
b. you could be a "Mule" for your friend and bring a resupply for them so they don't have to lug so much food from MTR or last resupply point (they will love you for it)
I also wanted to ask if there is some type of shuttle system that you can pay to take you back to onion valley from portal to pick up car???
Nah, drop the car off at the portal, then go to OV. It's always nice to have the car there when you finish. Not sure of cost of shuttle, but, it's not too hard to hitch a ride.