It took a long 7 hour bumpy ride from Kathmandu to get to Chitwan. I spent a couple of days in Chitwan, walking along the outside, taking an early morning boat ride, a short guided walk in the park, an elephant safari and finally staying in a rangers tower about 30 minutes into the park. Chitwan park is famous for its one-horned rhinos as well as other large mammals including tigers and sloth bears. I ended up seeing about 8 rhinos, many spotted deer, a few barking deer, two types of crocodiles and many birds.
The first rhino was actually outside the park and there were many people around. Rhinos are known to charge when agitated and you can't outrun then so the best solution is to run up a tree (if you can). Another option is hiding or if you have to, zig zag while running. The rhino I saw was getting a bit agitated by some of the stupid tourists who were getting quite close to it. I stood quite far away (with a good zoom camera) and near a tree.