Has anyone visited San Marino?

Even had a San Marinese girlfriend when I was living in Italy in my late teens (always loved chasing "foreign" girls). Although I have always driven there, however there was regular and frequent bus service from Rimini up to the top of the rock. I'm pretty sure they still do. Just find your way to Rimini by train, then the buses start from the train station. From Rimini to San Marino was about 30-40 min drive (traffic is heavy on weekends). The bus might be 45-50 min. It's a pretty town and a nice view too. Half day is enough to see the place, so I would make it a day trip. I don't think you need to spend the night. unless you pick up a San Marinese girl, in which case what happens in San Marino, stays in San Marino.

I knew I could count on Roberto!

If you drive, can you drive right into the country/city/hill town, or do they one of these challenging ZTLs? I realize your experiences in San Marino may pre-date ZTLs. As for picking up lovely San Marinese ladies, do you have any phone numbers for me? They do have phones In this tiny land, yes?

RSM always had a ZTL inside the ancient walls.
But there is parking in the various piazzas just outside the city walls next to the city gates. My strategy was to go to the very top place I could drive to. I think that gate was called Porta alla Fratta. There was a parking lot there, probably still there, although I haven't been back in years. If that one was full I would drive back and see if I could find parking in the next parking lots coming down. There were also street parking on Viale Onofri (I think that was the name). The trick is to start looking for parking from the very top because that will minimize your having to walk uphill from your car to the palazzo pubblico in the old city center.
No telephone numbers anymore. Decades have gone by since those fun times. Yes, they have phones. The RSM is a wealthy country, significantly more so than Italy. If you snatch a lady's phone number you might be set for the rest of your life. Low taxes as well. Unfortunately very hard to immigrate to it. Unless you marry a Sanmarinese, you are out of luck. They keep everybody out.

Roberto is correct about the parking lot at the top. Good size lot and street parking along the way to the lot. I would get there early and have pretty much the pick of spaces. There are loads of buses that go to SM but always had a car so can't say where they originated from. After you see the castles there isn't a whole lotta touristy stuff but I liked just wandering around and soaking it in. On a clear day the views are great. A lot of the shops have the replica weapons (guns/swords/knives etc). If you're into that shop around for awhile before buying. You can often find the same thing for less in other shops. Some people seem to not care for the place for some reason or another but I thought it was great. I would say if you're gonna be that close go! I always wanted to spend a night but never did. Like Venice, I would think it'd be a whole different experience after the day trippers cleared out.

San Marino is a duty-free supermarket that thinks it's a country. At least it is bigger than the Vatican, Monaco, and a couple of Pacific island pimples that claim to be sovereign. Wikipedia says about 34,000 people reside on its 24 square miles, much of that area being the steep slopes of its mountain. From the peak, the panoramic view of the surrounding countryside below, most of it Italian of course, is worth the trip on a sunny day.
One of its main sources of revenue, postage stamps that were pasted in collectors' albums rather than on envelopes, has dwindled thanks, like so much else, to e-mail. Duty-free means far less in the era of the European Union. So tourists in search of novelty are essential. I helped the economy with a purchase of a tiny, tacky glass snow globe, which seemed an appropriate keepsake.
Tip: Restaurant menu prices rise as you climb the citadel.