Started all my kids with with a ruger 77/22 and 3-9 Leupold. I would set cans out at 25 yards and set the gun on sand bags on a cooler. You’d be amazed how fast they learn to acquire their target. Start on lower power and let them decide when to crank the power up. Gradually move the cans cans...
My 12 year old has been shooting this Howa 1500 in a Boyd’s at one stock since he was 8. It is chambered in .270 win with mild hand loads 100 grain Barnes ttsx.
I have seen quite a few Toyota tacomas with pop up overhead campers trailering quads on ultra light trailers running around the west. Might be I viable option you can down size everything. Unhook the trailer and take the camper off the pickup. You’d have the option to ride the atv outta camp or...