You really don't need a tour guide in Monaco. It is really easy to do Monaco on your own. Just do a little research before you go to learn some of the history and which sites to visit. It is a beautiful place! Be sure to visit Prince Ranier's palace, the church in which he and Princess Grace are entombed, and the Casino. Also, near the Palace are many cute little shops that sell souvenirs, etc. You can walk all over Monte Carlo, but it is very hilly so you'll need to be in good shape!
You can easily do Eze and Nice on your own, also. Bus #100 (I believe) will take you to Nice and back. It also goes right by Eze Sur Mer where you can get off and wait for the bus that will take you up to the village of Eze. I think it is bus #83 that takes you on up to the village of Eze. Just ask the bus driver when he stops. (It should also be written on the front of his bus.) You'll catch the #100 bus at the bus stop right in front of the train station entrance in Monte Carlo! Have a wonderful time!