I stayed in the resort, and the number of things you can take kids to is minimal
Also, there is no cellular coverage, no wifi in the rooms, no fridge, no microwave oven
If you need a fridge, you need to deposit your DL at the front desk, which means you can't drive out to see places around
I feel you get a hot springs ticket and go there to stay. Better to stay in Fairbanks, where you get comfort, proper food, and a good experience sleeping