having done 2 similar trips over the past 3 years, here are some thoughts:
--cheap hotels? forget about it. not gonna happen. And in some areas (read: Denali) you'll find required 2 or 3 night stays in many hotels. Start searching now, and book what you can find up there. (We stayed at the Crow's Nest. It was fine, but not cheap and had a minimum stay. Liked the restaurant/bar!)
--consider this as an alternative or addition to the bus tour into the park: http://www.denalisights.com/. It's a monster truck tour of Denali, and you get to places you wouldn't see otherwise unless you hiked in 10-20 miles. It's expensive, but we LOVED it. The hard part is that the departure is about halfway between Talkeetna and Denali itself (at the Igloo, for those of you familiar with the area), so there's some extraneous driving involved.
--if you're going to Alaska to experience Alaska, and this is a once-in-a-lifetime type trip, skip the HH points nights in Anchorage and daytripping, and spend more time in Seward (in addition to the boat trip, visit the glacier, take the Ididaride tour with Iditarod dogs, hike out to the remote areas, visit the dive bars in town--they're great. And eat at Salmon Bake: Warm Beer and Cheap Food) or add Homer (a long drive, but well worth it), or spend some extra time in Talkeetna (flightseeing, some hikes in the area). It's not going to be cheap, but you're there to see Alaska, not Anchorage. The city itself is fine, but other than the stunning scenery surrounding, it kind of felt like Omaha. (Not a bad city, just not the kind of place you choose to travel thousands of miles and spend thousands of dollars to visit unless you can avoid it.)

Consider B&Bs or small inns to minimize the costs--but 1 night in Anchorage is enough! You'll land, grab some food, walk down to Sunset Point and watch the sun set (at midnight-ish, although it never gets really dark), and do a little sightseeing in the morning, but then head out to see the real sights.

Enjoy--it's a great, great trip!