How about home made ice cream and a chocolate fondue with dipping fruit. Make the ice cream right there on the river and cook her favorite dutch oven meal . The fondue is to start the meal.....and the ice cream goes with the birthday cake you were suppose to bring with you. Red roses for the table will set the atmosphere. After a few bottles of wine......the male kayak stripper you hired off mountain buzz rolls in for a quick lap dance.
Now you got her full of food, tippsy, horny, and ready to tear your clothes off.