Harbortown is a good marina. I've stayed there with our big boat that we had and the Publix and West marine are handy. There is a restaurant and bar at the marina, but that is all there is in this part of town. They do have a fenced in area where you can leave your vehicle and trailer and it is locked at night. Not sure I'd venture anywhere else close by.
City Marina in Fort Pierce is nice also and all the restaurants and shopping are right there. Not sure if there is a grocery store around. Haven't stayed there much as it always seems to be full, you might call ahead and get a reservation. Great area though. No place to park a vehicle or trailer.
We have quite a few marinas in Stuart. Sailfish marina is new and nice, located next to downtown with plenty of restaurants and great shopping. Loggerhead Marina is nice also but it is a little further to town, a good bike ride. I have stayed there many times, usually a great crowd and they have a nice restaurant also. They also have a separate small dining area next to the pool for marina patrons only. There are marinas in Manatee Pocket also but I have never stayed at any as there pricing always seemed high to me, but the night life is great there. These are all on the St. Lucie River. On the Intracoastal just south of the Stuart Causeway is Mariott Marina, good for a night, Publix is just a block away. Its on the ocean side of the river.
Someone mentioned the marina where the Deck restaurant is located, it is fair but the docks are old and dated. It is a good bike ride or walk to downtown Stuart. As for any marinas that may allow you to park a vehicle or trailer, I could not answer.
As for putting a boat in , both the Stuart Causeway or the Jensen Beach Causeway have great ramps underneath the bridges.
Hope this helps.
Mike McDonald