Keep in mind that it is not at all unusual for USFS or BLM campgrounds to have NO dump station! While there may be vault toilets, it is usually against the rules to dump RV waste in them. There is a set schedule for pumping them out, and the Forest Service does not want them getting full too soon.
When camping in such campgrounds, water conservation and management is vital.
Not only will there likely be no dump station, but there may be no practical way to refill your fresh water tank.
When you run out of water, and your waste tanks are full, you will likely have to go to the nearest town to refill and dump.
Here in Montana such campgrounds are the rule, rather than the exception.
Just something to think about....