Schnitzel...in August? Yes! (and more)
Morse's Sauerkraut and European Deli, North Waldoboro
Morse's makes wonderful brine-fermented sauerkraut and pickles, has a shop with a dizzying array of European foodstuffs, and a great small restaurant serving a menu of European dishes and sandwiches, including excellent Reubens, Pierogies and, if you are really hungry, a Schnitzel supper. On my last visit, I had an outstanding Jager Schnitzel with wild mushrooms, buttery spaetzle and red cabbage. I strongly recommend shopping before you eat, because after a very hearty and excellent lunch, you probably won't be able to think much about further consumption. Note that it's closed on Wednesdays, but otherwise open year-round.
Jo's World Famous Schnitzel Wagon
In a tiny food truck set back off Route 1 in Machias, Jo's has classic schnitzel as a basket with superior French fries and red cabbage, as sandwiches, homemade bratwurst, fruity lemonade, poutine, great dessert and specials. Do call first to confirm hours.
not schnitzel - except maybe in September and October - McKay's Public House, Bar Harbor, Maine
I can't claim objectivity about McKay's since they are good friends. I will say that it is a righteous gastropub and you will absolutely not be disappointed.