I'll second the Sandpoint recommendation. The family just loves the area and the roller coasters at the amusement park are fantastic! May have to wait for the kids to be a little older to go on them but there are lots of other good rides there, too. The amusement park and the water slide park are connected so we find that on hot days (of which there a lot in that area) you'll go do rides in the amusement park and then change into your swimsuits and cool off at the waterpark. Rinse and repeat throughout the day.
The drive time is 6 hours but usually find there is a wait of 30 minutes or so at the border on the way down. Coming back, it is usually 10 minutes or less.
Will put in a plug for Scotch Creek, as well. We've stayed at Scotch Creek Cottages (
https://www.shuswap.ca/ a number of times and really enjoyed it. Great common area with around 20ish cabins surrounding it. A longer drive, though, to get around to that part of the lake. Usually around 7.5 to 8 hours.