There are several campgrounds on Superior National Forest near Ely.
I suggest that you visit the following website and look at the Kawishiwi Ranger District (that's the one in the Ely area). Fall Lake is the most modern, but you should make reservations ASAP, as it is popular and fills up fast. The other USFS campgrounds are more primitive. They have no electricity, but they do have water available, but not at each camping spur. All of the USFS campgrounds in Ely area are located on lakes.
linkIt is unclear as to whether you are planning on going into the BWCA Wilderness or not. That is a wilderness area with no roads. Most people travel by canoe, but there are some trails as well. If you plan to go into the wilderness, you will need to get a permit and also leave your motorhome somewhere. You could leave it at a BWCA entry point, but I wouldn't leave a motorhome there for any length of time. If you use an outfitter in the Ely area, they will likely let you leave it on their property.
