I usually take the hill in my big ring on the 3rd easiest gear in a spin. Alternatively I throw the chain to a hard gear and mash up the hill standing. I almost never go to a small ring, even on my commuter bike. I think the maximum grade is 4.2%, not nothing but not a steep hill either. For a beginner it is good to get started but it won't prepare you for anything bigger. River Road (actually Henry Hudson Drive on the map) has the hill at the end in Alpine NJ. That is a hard hill that is repeatable if you feel like doing it again after the first time, I never do!
I was training for a climb of Mt Haleakala in Maui a few years ago and did some repeats on it, except that getting back to the bottom took too long as there isn't an easy loop around. Central Park is easier to repeat that way since the cutoff at the top of the hill brings you directly back to the bottom. I won't ride wrong way in either park, it drives me crazy when I see someone doing it. Haleakala is an average 5.2% for comparison, and that I took entirely in the small ring and large 2 or 3 cogs. By the time I quit (I didn't make it) I was wishing for another 3 or 4 cogs!
Look for an older guy on a black Kuota Kredo and that's me. You don't see too many Kuotas around anymore, not that you ever saw many in the first place. I'm not sure they are still being imported.