Rocks for me so far. I just took delivery last month and have only had it out 3 times, but it seems to work fine. I get close first and then toss rocks as needed. 4 low helps when trying to put a tire on the rock for me
Sometimes using the lego block style and other times using rocks or wood that I find around camp. I am intending to install a level in the cab that I can see from my driver’s seat to make the process a little quicker.
Just find a level enough spot, park the truck and go to sleep. Don’t over think it. For me the point of the gfc is simplicity. I’ve gone down rabbit holes with my gfc and haven’t really had an overall better camping experience the more complicated I make it. For me it’s a tent built into my truck camper which for my purposes is great.
I just picked up a pair of GoTreads that work really well for leveling. Ive also installed a bulls eye level near the shifter for super easy visual access. The less I have to hop in and out of the truck, the better