With only a week to spend, I would definitely skip Wrangell/St. Elias NP. You really just don't have the time.

You could do something like this:

Day 1 arrive ANC get RV, grocery shop, maybe grocery shop, to Palmer

Day 2 State fair, maybe Independence Mine, Eklutna, Iditarod HQ in Wasilla

Day 3 to Talkeetna, flightseeing (7pm flight has 2-for-1 coupon in Toursaver book)

Day 4 to Denali, some activities near the park entrance, drive to Fairbanks

Day 5 all-day shuttle bus to Wonder Lake (not Mirror Lake)

Day 6 to Fairbanks, afternoon activities there

Day 7 am activities, start drive back to Anchorage

Day 8 arrive Anchorage

You could make it from Fairbanks to Anchorage in one day but I would plan on 8+ hours - RV's go slower than cars, some traffic, road construction delays, etc. You never know in AK in the summer. Some roads have been closed for days at a time due to roads or bridges being closed.

End of August should be amazing for the fall colors in Denali.

Don't be in a rush to get on your cruise ship. You can either get a kayak tour in Whittier or take one of the excellent Prince William Sound boat tours. The timing of the PWS tours works great with the train or some shuttles from Anchorage - start about 1pm, end about 5pm, then you can get on your ship for dinner. You can drop your luggage off before your PWS cruise and the boat company will keep your carry ons. You get much closer to glaciers on this small boat than you ever will on your cruise ship.

John