The website states: Note: The Wheeler Peak Scenic Drive is narrow, winding, and climbs an 8 percent grade in 12 miles. Wheeler Peak Scenic Drive past Upper Lehman Campground is closed to single vehicles or trailers in excess of 24 feet in length.
I would assume that as long as each vehicle is 24 feet or less, that you'll be OK. However, I would not want to be the one to head up there and find out that assumption is wrong.
As Naio recommends try emailing them at grba_interpretation@nps.gov or calling at (775) 234-7331 and getting the correct information directly from them.
