Park somewhere else and take a cab or bus. The fairgrounds are easy to reach, and you should be able to find someplace else to park, even if you have to pay a few bucks. Do you have campground reservations already? I think you might need to check into that. And the camping around Albuquerque on Forest Service land is not open to all:

All developed recreation areas on the Cibola National Forest allow camping except those on the Sandia Ranger District, which are for group camping and day-use picnicking.   Most campgrounds are more than an hour's drive from Albuquerque; Tajique or Fourth of July campgrounds on the Mountainair Ranger District are nearest and are approximately 50 miles from the Albuquerque city limits. Developed campgrounds have a 2-week camping limit during any one visit. The Cibola National Forest has no national forest administered cabins or lodges. More information here.

It should be hot and beautiful in Albuquerque. Take time to poke around some of the older neighborhoods (park at the Sheraton or the museum north of Old Town and walk from there--the streets are too narrow for RVs).

SRS