Google traildamage.com They are a good source for off road trails all over colorado and other states. As far as a rental place, I have no idea. Just a FYI Estes will be insane with crowds coming in town to check out the elk. You will be amazed with how close stupid people will get to them. prob not a bad idea to bring a video camera, you might get the chance to see some dumb a$$ get ran over buy a bull.
Hope the website helps.