the drive over tioga pass has terrific scenery and you will want time to stop and take it all in and the the going won't be quick on the mountain pass so if poss get an early start. i can't say about the tour as such but the park has a free and very frequent shuttle bus system that goes to all the main parts of the valley floor,so that is an option.
with an early start and late finish [not sure if you have kids to consider]i would try and find the time to drive up to glacier point late p.m./early evening for a look at the view that is the best i've seen but it would make it a very long and tiring day. worth it? definately!!
have a great trip.
there is a garage at the junction with the 120 and 395 just out of the town in lee vining. at the back of the garage there is a diner called "woah nellies dellie". it's the worst kept secret in the area,the food is great!!!!