From multi day backpacking, I've learned to stay away from deet based repellants - once you use it where showers aren't possible everything you eat tastes like deet the rest of the trip. The solution I found was to treat a set of long sleeved/legged clothes and our shelter with permethrin spray before a trip. We found that once we set up the bugs left the area.
After a particularly buggy trip to Cape Disappointment SP, I treated our under awning
bug net with permethrin with similar results