@mrswillson, I really couldn't give you a good estimate of our cost. It was booked independently in 2008(EEK, almost 10 years ago, when my youngest graduated from high school!!). I chose individually everything we wanted to do, we were busy just about every day and booked everything myself. I planned this huge trip, naively thinking we were going to do everything we wanted because we weren't ever coming back. That turned out not to be true!
I think you could plan a trip for that amount, especially if it's Denali and the train and you're excluding excursions and airfare.
One thing I can suggest. Look at the Princess Lodges.
https://www.princesslodges.com/. They have their own tours. What I did was pick and choose things from there that interested me and a few other travel experts and pieced together what we wanted to do.
The summer we traveled, it was stay one night, get one night free at the Princess Lodges, so we did take advantage of that. We stayed in 2 of them, one at Mt. McKinley, the other at Copper River.
We stayed in Achorage at a local hotel within walking distance of the train station. We then took the train to Seward. Husband and daughter did a glacier dog mushing excursion. We did a boat tour on Resurrection Bay and went to Exit Glacier. Then took the bus back to Anchorage. Picked up a car and drove south to Whittier. On that drive we saw a beluga in Turnagain Arm and a black bear just walking down the road! Then back through Anchorage to drive over to Valdez and did another boat tour on Prince William Sound. We then drove North to North Pole, Alaska and Fairbanks (In hindsight, I could skip this). We then drove South to Denali staying with the only sanctioned Dog Musher in Denali, at the time, at his hotel in Healy. Did the long Denali (12 hours) bus tour and loved every single minute. Stopped in at Talkeetna, just to look around, and then stayed at the Mt. McKinley Lodge(Princess) on the way back to Anchorage.
One important, very important, suggestion is that if you drive independently in Alaska, you need to buy a copy of The Milepost. It was invaluable for gas stations which are few and far between and saved us a couple of times.
If you would like any further information, just ask. Huge Alaska fan and I hate the cold!
