Family trip to alaska for 9 days
 

Hi trusty Fodorites!
We are planning a last minute trip to AS, hoping you can help pull it off - From July 31- Aug 9th.
So far, I have the alaska railroad one-way from Anchorage to Denali booked, and a 3 night stay in Denali Natl Park. I'll have to book a motorcoach ride back to Anchorage on Aug8th.
I need to plan the first half of the trip after we land in Anchorage on July 31st night. Seward, Kenai Fjord and anything else that can be accomplished between July 31 - Aug 4th.
Also, we may most likely not get a rental since it is super pricy at $250 per day! But we need to evaluate if it averages out if we were to take day tours just to get from point A to point B and also lose out on flexibility, in which case the steep per day rental is still a better option. As I noted earlier, Aug 5 - 8th would be in Denali and we wont need the rental. I would highly appreciate your feedback. Also, I have 2 kids, almost 9 and 10 years old and would like to do the Matanuska glacier,Kenai Fjords National Park Cruise and dog sledding.
Also, vacillating between another train ride from Anchorage to Seward or take a rental and stop at all the scenic spots.

Looking for suggestions!