The route profile suggests that the more difficult part is between mile 70 and 80 (three summits), then a net elevatiuon loss until around mile 95 and then a climb to near mile 100. It's the closely spaced, back to back to back sort of climbing that wears on me since the downhills never seem to last long enough. Then again, one of the more taxing rides I lead every year is 69 miles of flat to every so slightly undulating in places in Cumberland County, NJ. It's taxing for the reason you note; it's constant pedalling.
From the profile, it doesn['t appear that you have anything over 5%. And most of the hill sections average 3% or less. That should take less of a toll on your legs. If I were doing this ride, I would try to conserve a little between miles 40 and 70 (the 40-50 elevation loss looks like fun) and between 80 and 95.
Good riding. It looks like an adventure. But one word of caution. Be careful on 147 through Nothumberland. I drove through there a few years ago on the way to a backpacking trip. Crazy traffic, including a lot of trucks, at the intersection of 147 and U.S. 11 and through Northumberland itsels.