I agree with the feedback you've received and would add that it would be a shame if you made Monaco your base for a stay in the area as it justifies a visit (if you have to ......) but probably not a stay. It's an experience rather than a vacation destination imho. The 110 is the best way for normal people to arrive in Monaco unless you have cash to burn.

If you decide to visit and want to visit the casino and wish to avoid the possibility of being turned away then keep your passports with you as they might ask to see them because normal residents of Monaco are excluded entrance.

You may be interested to know that many visitors see feature films and racing games that are ostensibly filmed in Monaco but Monaco bans the majority of filming requests and most are fullfilled at Beaulieu sur Mer which is down the coast and has a Casino that is somewhat similar to those that don't know - in appearance to the one in Monaco. So don't make your plans in such a way that you miss out on the better gems between Nice and Monaco.

Consider basing yourself in Nice or nearby and getting up early one morning and taking the 100 bus from Gare Routier which will take it's time along the coast road to Monaco. I think it costs a euro all the way ..... and then take the train back ... perhaps for lunch on the way back. A day out and a decent bus ride. is all that Monaco justifies imho.