If there aren't any restrooms nearby (and even if there are a few), you should consider renting them. These days, you can find luxury portable restrooms with amenities like in—room music, granite countertops and air conditioning or heaters depending on the season.
Remember to: Give guests something to talk about with a few subtle extras like luxe soaps, fresh flowers and monogrammed towels.
Bonus tip: The general rule of thumb is to have one bathroom or stall for every 35 guests. This way, guests will spend less time standing in line and more time partying on the dance floor.