You didn't specify what areas of northern Idaho, so check out these links for information
Campsite PhotosIdaho Campground ReviewBLM CG with Hookups - you can find the other BLM campgrounds here too, but most don't have hookups.
If you are a Good Sam member, they have a great campground directory of areas along with ratings. In general you can Google the area for campgrounds and even use either Google Maps with the satellite settings, then zoom in and you can usually find RV parks in each town, then Google the name for reviews and information.
We've stayed at Priest Lake, but they only have water and electricity hookups. Winchester State Park also has the same hookups, but also a dump station.
Hope this helps.