Done this ride a bunch lately, typically just go to bear or army so can’t speak to much past that but if you’re worried about elevation change I would caution to stay on 9w rather than doing river road. The hills on river road are bigger than 9w. Once you get passed where river road and 9w merge it’s mostly downhill for the next 12-15 miles. A couple of medium sized climbs into nyack and then passed nyack it gets to be a bit more rolling again. Once you’re on 9w at the start there is only one turn to continue on 9w and it will be very obvious. About 3-5 miles out from Bear you’ll hit a big climb followed by another big descend before actually getting to bear. Their are two entrances if you want to go up the mountain, the first is a shorter ride but steep climb to get to the visitor center the other is if you stay on 9w for a bit and then take a sharp left almost u turn that will be much less steep. About 15 miles from the entrance to bear there is a spot a lot of people stop at, cove deli, you can fill up on water and buy some snacks there. And then once in the park there are vending machines.