Lincoln Brook and Liberty Brook (unlabeled on AMC map, comes down off Liberty/Little Haystack) en route to Owls Head on the Lincoln Brook Tr. Bushwack due north from the end of Black Pond Tr. @ Black Pond till you hit the brook to avoid the first crossing of Lincoln Brook and Franconia Brook on the Lincoln Brook Tr. Liberty Brook was tricky, but I barely made it dry w/o wading when I was there on Memorial Day a couple years back.
Thoreau Falls Tr. crossing above Thoreau Falls. Big consequences with this one! Although not on the way to any 4K footers.
Gale River is tough at high water on the Gale River Tr. on the way up to S. Twin/Galehead.
The Rocky Branch near the Rocky Branch #2 shelter on the way to Mt. Isolation. 3 of 4 crossings en route to Isolation on the Rocky Branch and Isolation trails can be avoided by bushwack.
Maybe some of the crossings on the Cedar Brook Tr. on the way to the Hancocks. Some of these can be avoided by bushwack as well.