That museum is great, and Drumheller itself can be fun to stop at and look around. Make sure you grab food before the museum as it can take awhile (you can also pre-order tickets/slots which can help with the line).
If you're going up to Edmonton, there's plenty of stuff at West-Ed Mall. My kids loved the water-park+slides and the Lego store. There's also an amusement park with rides
Ironically, the local Walmart has been closing them all later in the day so that people must use cashier's, presumably due to increased theft etc