We went through there on our way north to AK, there is a nice COE park right off of US-2 midway between Newport, WA and Sandpoint, ID. Nice big, private sites and real quite. Newport had a rodeo going on which we found very interesting (being easterners) and Sandpoint gets a lot of summer people and a nice place to vist, eat and what not.
RV Park Reviews :: Oldtown, Idaho ( ID ) - RV Parks and Campground Reviews
The CG is in Laclede, not Oldtown, but the google map link is good. We ended up spending a week and enjoyed it. There is a dam down the road with a visiter center.