If you had a dinner reservation you should be able to park at the hotel where you are dining at no charge. The monorail hotels are the Polynesian, the Contemporary, and the Grand Floridian. You can ride on the monorail for free. You can get off at each hotel and explore a little, there are gift shops and quick service food, and then get back on to the next stop, etc. If you want to go all the way over to Epcot, there is a different monorail for that which you would access by getting off at the Transporation and Ticket Center Stop and switch over to the other line. I wouldn't really recommend doing that because there isn't anything outside the front gate of Epcot to entertain yourself with, but the monorail does drive over future world in Epcot, so you can look at some stuff from the window, but I wouldn't get out of the monorail at the Epcot stop since there isn't anything to actually do there.
Just a tip, if you are dining at one of the monorail resort restaurants, you should be able to get a view of Wishes if you time your dinner right, check a times guide for fireworks time, or check it online. From the Poly, you can watch wishes from the beach or dock. From the Grand Floridian you can also watch from the marina area or dock outside of Narcoosee's, and from the Contemporary, you can watch from the viewing area on the 4th floor, the walkway between Bay Lake/Contemporary or it can be watched from the parking lot or sidewalk outside.
The monorail does not go to Hollywood Studios or Animal Kingdom.