Monkey is dead on. If there are issues with the infrastucture, you could have a money pit instead of a viable business. Water and electric are important, but sewer is the key. If the septic needs updating, new laws may make it cost prohibitive. What condition are the building in? Renovating an office, the restrooms and other buildings can cost several hundred thousand dollars if you do it right. And don't forget it is going to be very hard to get financing for this park because it has no current financial statements or records. Personally, I wouldn't buy a park that wasn't operating and didn't have a track record. I want to have a good idea of my financial risks before I spend my money.
Forget about snowmobile traffic if you want an RV park, keeping a park open in the frozen north is very difficult and not very profitable, hence why almost all RV parks in the north close for the winter.
On the other hand, if the river and location is a good drawing card and you can buy it for the right price, you might find you have a diamond in the rough, but be very careful because if it turns out to not be viable, you won't be able to recoup your investment.