I find the ride back from Bear Mt on the west side to be something of a chore. It isn't great riding, the towns are a lot uglier than you'd think on the river because they were basically industrial towns.

Speaking of NYC bridges for hill climbing, I do a 4 (actually 5) bridges ride occasionally. I start at the Brooklyn Bridge on the Brooklyn side before it gets crowded, cross, take the Manhattan bridge back to Bklyn, then ride up to the 59th St bridge, then down to the Williamsburg Bridge back to Brooklyn. I vary the order sometimes. The 5th bridge is the Pulaski bridge between Bkln and Queens. That bridge has a new bike lane. It gets some climbing in without having to leave the immediate vicinity of Brooklyn. The bridges themselves are easy enough that you never leave the big ring, but still a little of a hill workout.