There is no restriction at the ramp or the facility. If you get there early enough you will beat the fee but plan on paying when you get back in. The old lady or man will probably be there to square up. Hope this info helps.
I have always beat the attendant on the launch but Paid the Piper on the return trip.......Last time there though, I was in before.....and out after the atttenant.......I was'nt sure what to do.....I walked around that shack three times looking for some direction or a money slot.....I guess I can chaulk that one up as a freebee.......never got a ticket in the mail anyway.
One day is 5$ for MD boat 10$ for out of state. Their pretty strict about it, at least the old lady is. And don't use the far left ramp when you return to load your boat or you'll get yelled at, learned that the hard way my first time there before the marked it unloading only.