Definitely check out canyonchasers.net if you are looking for some scenic routes on the way to WSBK that have twisties.
http://www.canyonchasers.netSome of the canyons will not be open by WSBK, but usually a good number are. So far we've had a mild winter here in Utah, but we still have a couple of months to go r.e. the snowpack count.
As for camping, there are lots of options. The Wasatch front isn't that far from Tooele (about 40 minutes), and there are also several campsites to the Southwest of MMP, within an hours ride.
Bring a warm sleeping bag. Temps can still drop near/below freezing at the end of May (not usually below freezing at night, but it happens, especially if you are at a higher elevation).
The Bonneville Salt Flats (where they do the land speed record thing) are usually still soggy in May - most of the events at this location are later in the year.