Thanks everyone. The rough finish will require a brush with soap/water to clean. Over time, it may need something like a rubber/plastic treatment (ArmorAll, Tire Shine or something). The cured Herculiner feels rubbery, stretchy. Should be good for what is intended. For what we did here, a gallon was way more than enough. The gallon kits included a roller, brush and a Scotchbrite pad.
The wheels will eventually be black as well. Sarah hadn't heard the term "Murdered Out" till about a year ago. She's a little goth, so she liked that moniker. I'm suggesting BFG A/T tires, but we'll see. Tires/wheels are a big chunk of change to spend on a secondary vehicle...
By the way... wife, daughter and I spent a few days in Glacier National Park (we drove our 2001 GMC). Was way too crowded, being over the 4th, but the weather was perfect. I'm mentioning it because among the throng of vehicles I saw there was a 6.5TD camper on an HD 2500 chassis. An RV company produced these for a time. Sorry I didn't get a photo of that camper... That one was blue. However, a member attended our 2000 Rendezvous here in Montana with one of these campers. This is a photo from that 2000 Rendezvous.