Our family if 2 girls (ages 12 and 8), their grandma and us will be flying into Anchorage in Aug. we enjoy hiking and the outdoors. after 1 night in Anchorage we would like to drive to Seward and spend 2 nights there. We then plan to drive up to Denali and spend 3 nights there. On the way back we are thinking of driving to Valdez and taking the ferry to Cordova spending 1 night and returning to Anchorage through Whittier. Please advise if this itinerary makes sense in terms of sequence of places bring visited and days planned per city. Valdez and Whittier seem to be the only ways to get to Cordova. Is that an accurate assumption ? We are considering driving up to Fairbanks to attempt to see the northern lights if it makes sense. Please advise if we should fit any other must-do item on our list.

No, you probably won't see northern loghts in august. It will still be daylight for many hours. In june, it never got dark, just dusky where we were.
Stop at indepemdence Mine on way to enali. fascinating history. Whittier is the only town we would not care to visit again but DH just had to drive thru the tunnel. Itwould be easier to substitute a different town than cordova and i recommend Homer.

How long are you in Alaska? I am assuming 2 weeks. I hope you have already booked your car rental. Cars are expensive to rent in Alaska.

You need a stop between Seward and Denali. We enjoyed Girdwood. There are some nice hikes there. You could take the ferry from Whittier(about a half hour from Girdwood) to Valdez.

I can't advise you on Cordova but we too loved Homer.

Click on my name above to bring up our trip report from last summer. We would have loved to have gone to Valdez but couldn't get it in our itinerary.

Skip Fairbanks. No northern lights, and not much else to recommend it, IMHO.
Whittier is just OK. The drive through the tunnel is interesting, or maybe you'd go there for the glacier cruise.
Girdwood is a good stop.

I am planning a similar alaska vacation in 3 weeks.
Click on my name and you will see some posts with the itinerary.
I skipped Cordova as the bridge to the Child's Glacier is closed.
The drive from Valdez to Anchorage through the Glenn Highway is supposed to be very nice.