The only reason I can imagine a multi-storey RV park making sense would be to take advantage of some weird zoning quirk or something. But that's a lot of money to throw at what's effectively a legal vulnerability that will probably quickly be fixed.
From a cash flow perspective I started with parking garages as a business model. The typical 'monthly parking' type garage is a concrete and steel affair with sprinklers and elevators as its biggest operational expense, a bit more if you add an on-site office for an attendant to capture additional revenue from special events.
All the space that requires maintenance in an apartment building that is 'non-apartment' doesn't exist in an RV park. You don't repaint or re-carpet, you don't send HVAC dollars on cooling or heating, Etc.
My assumption (and I'm open minded about missing things) are that using the ratio of comparing of a traditional RV park to a one story apartment complex is a valid way to estimate expenses and cash flow. Then to extrapolate by adding additional layers to the RV park. There are also different tax treatments but I suspect that if the difference there appears to exploitable that it will be quickly changed.
The biggest complaint about RV parks are that they are RV parks and they are an "eyesore". By enclosing the park you can improve the optics, and by increasing the density you grow the ROI relative to an apartment by the cost ratio. But is it a $5M project, a $10M project, or a $25M project that I don't know yet. And while a casual polling of city folks about which would they prefer, RV's parked on the street or parked in an externally attractive structure set aside for them, polls favorably, it isn't clear that is enough to get final approval.
Then have underground hyperloop tunnels to connect the RV parks, so that you can go to sleep in your home and move it from city to city, and pop up above ground to enjoy local tourism.