Don’t bother with the Grand Casino. We were very unimpressed with it all. The lobby was free to get in and we wandered around that a little and saw the Dali exhibit there. Kind of interesting.
You could have lunch on the Grand Prix circuit by the harbor, if you are into motor racing. Both are expensive – More to do I would say in Monaco and roundabouts particularly down the coast towards Nice and the villages in between . Monaco can get a bit claustrophobic though.
Monaco is pretty expensive if you need to rent an apartment, unless your husband’s job pays for it. It also depends what your budget and needs are, kids, etc. Cote d’Azur is generally expensive, but you can get good deals if you look in Nice. The little towns just next to Monaco, have become quite expensive too.
Near your hotel there is not a beach area. However, more toward the center of Monaco there is the beach front area of Lavrotto with a number of cafes etc…, a some beach club type establishments with chairs and umbrellas. There is also the Monte Carlo Beach Hotel (which is technically a few hundred yards over the border and in France) that is at the opposite end of Monaco from where you’ll be.
I believe that you can get day access to the beach club for a cabana or poolside (GORGEOUS POOL!) relaxation- though access starts at something like $70 for day use if you are not staying at the adjacent hotel or one in it’s group.