RV Parks are expensive to build. There are many government requirements such as waste treatment, water treatment, environmental impact studies etc. that have to be met. Suitable land (close to a desired destination or city) is very expensive. RV parks are generally not considered good neighbors (neighbors see noise, traffic and run down trailer parks) so there is often opposition. Construction loans for RV parks are virtually unavailable, so a park builder has to pay for the construction out of pocket. It takes several years to build a client base and for advertising to take effect, so they need to be able to handle negative cash flow for several years. You may see a park built in a financially bullet proof location or one built by an individual a few sites at a time, but I wouldn't expect to see many mid size to large parks being built in areas where the customer base will mostly be travelers. Too Risky and expensive.