Might you be willing to elaborate at "I get turned down at most parks"? I have not had this experience.
When we call ahead to make reservations, we state we have a big truck, mention it is the size of a UPS truck.
This has worked every where we have tried it, this method was suggested by someone on this forum(thanks to whomever this was).
We had one Buffoon in Georgia mention that we should have let them know it was a "Semi" truck as they would have told us no, due to weight. They did let us stay. My friend had his 42 foot motorhome, that by itself weighs more than my truck,trailer and toad combined. Funny they did not say anything about his weight?
Michael