The Coeur d'Alene Summer Theater has top notch productions that run throughout the summer: http://www.cdasummertheatre.org/Home.asp
Many productions sell-out, so buy tix in advance.
If you happen to get delayed until August, the Festival at Sandpoint also has good entertainment: http://www.festivalatsandpoint.com/tickets.html
The Route of The Hiawatha is an entertaining way to spend a day:
Comments on Sandpoint lodging: The LaQuinta is much nicer than the Quality Inn but is more $$$. I have stayed at both a number of times. When I am by myself, I go cheap but with the wife it is the LaQuinta (formerly Connies) The Best Western is ok near the city beach, but I don't care much for the Lakeside Inn, in the same area.
If you are staying C d'Alene, I suggest going to one of the B & B's. The Coeur d'Alene Resort is nice, but I am to cheap to pay the $$$ and most of the other hotels are run of the mill chain hotels near the interstate. There is a new Holiday Inn Express right at the NW Blvd. exit, which I would guess would be the nicer one of that type of lodging. The owners of the local HI Express franchises do a better job than most.
Anyhow, if you have questions, drop me a line and I will try to provide more info and phone number.
Yeah, I know not too much skiing info, but even if this is your only visit to the area, it should be fun.