I would rent a car from Avis. No need to drive all the way to Anchorage as there is plenty to do in the area. Hike to Byron Glacier, stop at the Portage Glacier visitors center. visit the wildlife conservation center, Stop in Girdwood and ride the tram to the top of the mountain and stop at all the scenic overlooks along Turnagain Arm. This is a really beautiful area with plenty to do. Just know the times for the tunnel so you are not stuck waiting a long time to go through.