Open Water Swimming and The Law

Here in south-central Pennsylvania, there are not many places to do open water swimming. That may seem hard to believe, but most of the rivers/lakes are either on private land or pretty nasty places due to pollution (farm run-off, esp.) The few places that there are to swim are usually in parks and are regulated out the wazoo. (A friend of mine was arrested earlier this year for training out of bounds at one of the state parks.) For those of you who do freshwater training swims, how do you deal with/circumvent the legal issues or do they not apply in your area? I realize that saltwater swimming is a different story, but we are several hours from the nearest saltwater - too far for regular swims. Or is freshwater training all "Jersey legal" - i.e. legal as long as you don't get caught? -LBJ