When I first joined this site a few years back, there was only an "HDT" (and maybe "MDT") truck sections. It took a lot of persuading to get the sections you see now -- Class A, Class B, etc.
So in the meantime, try the IRV2 Truck Camper forum.
We've both hosted and stayed at a number of Oregon state parks. They are consistently the best parks in the country, largely because of the funding that is now being reduced due to the COVID pandemic. Oregon parks are not funded by the state, but instead receive their funding from the lottery and park revenue. Both of these have been severely impacted by the pandemic. Personally, I'll pay the surcharge - the parks are still a reasonable price when you consider the quality.