Before I retired, I prepped beds for Rhino linings of Summit Station. Start to finish, including masking, took about 1.5 hours. For prepping the bed (scuffing) we used a grinder/polisher with a 4" fiber cup brush. This made short work of the the scuffing process, usually about 20 minutes, even on an 8' bed over the rail. With the Rhino material, coating thickness was about 1/8 to 1/4" thick. With just me (except for the spaying) I could prep 3-4 trucks a day. I don't miss it at all. Yours turned out good. Very nice job. God bless, stay well.
“It is definitely doable but I am straight up NOT having a good time. Trust the process!” He says! I would be a rich man if I had a dime for every time I had been there and done that. Probably why I am watching all of these DIY liner videos instead of just getting out there and starting to prep (sand) the bed of my next project. Pennsylvanians have a great sense of humor and a unique way with words. Good on you, tried and true, Americans.
For those valleys. You might want to try one those plunge cut oscillating cutter rigs like Rockwell makes. You usually use them to do metal or wood cuts but they also come with sanding heads that are hook and loop. You would need alot of discs and I would go with a rough grit. It will make the goop stick better and if it sands better it sticks better. I will try the canned version of liner.