excellent hike! from the tailhead you're looking at approx 7.5 in and out. you can also walk the creek trail and end back at Old Faithful Inn. bring bear spray.
It takes less than an hour to get to the hill from town on foot, you can opt for a taxi too of course. To get to the peak you can take the escalator or elevator. Very crowded for sunset! I'd recommend coming earlier or after to avoid tourists. The view from the Hill is amazing, you can see whole city and around! The pagoda on the top is nice, people come to pray there.
Another great viewpoint with really pleasant way to. Hike is a bit demanding at some parts but doable. We went there twice, once in the morning and once for the sunset. The latter was definitely better! The sun goes down with beautiful colors.
A bit touristy but nice, mountains emerge from flat surroundings. While you're there you might be asked by local students to have a chat with them so they can practice english with you.