You can go to Fruita and drive the NM road to the campground without going through any tunnels. But the road is steep, winding, and relatively narrow on both ends. Plus the campground has no hookups, no water in the spring or fall, and, if I remember correctly, no dump.
Personally, I would take DaveG39's recommendation and leave the trailer at James M. Robb Colorado River State Park. We have stayed there and it has some very nice, paved, FHU campsites with shade, tables, flush toilets, showers, a dump for the elect/water sites, fishing, and is right next to the river if you have a canoe or kayak. It is our only highly recommended campground in the Grand Junction area or when we are using I-70 to Ridgway State Park (one of our favorite Colorado SPs), Moab-Arches-Canyonlands, or Nevada-California.
"Retirement is the best job I ever had!"
2015 RAM 2500 4x4 crewcab 6.7L CTD; 2016 Rockwood Signature UltraLite 5th wheel