Unless you are used to what large clouds of blackflies can mean, I suggest you do not start further north. May 15th you are as close to being guaranteed blackflies in the ADK’s as it gets. Even the FLT can be bad in spring, though this usually happens around May 1st. They have a 4-6 week hatching cycle, and not as bad as further north.
I usually manage with them, because the trout think they are food…good fishing. I might get a few bug bites, but generally very few. I have seen people without a single square inch of exposed skin not bitten. Legs, arms, face and neck a mass of welts.
1) Keep moving.
2) Use permethrin on everything (‘cept undercloths.)
3) Spray everthing with DEET at least once per day, after every stream crossing.
4) Coat your hands, face, ears and neck with DEET.
5) Liberally coat your hair and hat with DEET.
6) Wear bug proof clothing, unknitted nylon or poly is best. Tuck your pants into your socks. Wear rubber bands around your wrists. Use a tight fitting collar. No buttons or other holes in your cloths. Wear a head net if they get really bad.
7) Light a smudge fire…one with a lot of smoke. Smoke cigarettes or cigars. Take a bath in wood smoke…it slows them down a LOT.
They need to eat through your skin, so they can be wiped off before that happens. Alcohol works well to sterilize a bite. Then a bit of Afterbite or ammonia. Two or three repeats over 15min or so will mostly clear up a minor bite. Yes, it will sting.
Head into PA and not worry about it… Sorry, that is a bad time for many.