Hi Laurence!
Sorry if I’m too late in replying to your comment… I’ve only just seen it but think I could be of some help!
I recently got back from Cuba where I was staying with my boyfriend Leo in Vinales (who’s Cuban). I had also thought before this trip of renting a car, but had the same outlook as you probably: expensive, can’t book in advance, will end up being more hassle than is worth. There isn’t a lot of positive information on the internet about hiring a car, so I gave up and didn’t reserve one. I then spent a lot of money on taxi collectivos…
Whilst I was out there I mentioned to Leo that I’d like to rent a car to get off the beaten track of Havana-Trinidad-Cienfuegos-Varadero etc. Leo said it’s super easy + cheap to rent a car, so one day we spontaneously went to Pinar del Rio (wouldn’t recommend spending much time there btw…!). We went to the main hotels that all have Rent-a-Car, and we went to some smaller places as well. We were out of luck hiring that day, because basically there weren’t enough cars. They all looked at us like we were crazy because we hadn’t rented online before coming. It turns out most people reserve their cars weeks in advance.
We later ended up in a smaller village near La Guira where there was a hotel that also had Rent-a-Car, and had available cars! It cost $80 per day (I think this was too expensive, talking to many people if you reserve in advance you can get it for $40 a day). There was the usual insurance deposit to pay, just as you’d expect, but it was all super easy from then on.
Anyway, I hope this insight helps. Basically, and from experience, I would strongly recommend you to reserve (with Rent-a-Car) before you get there. The easiest bet is probably via the bigger hotels in Havana because they’ll have more cars there. The cars are modern, often automatic. You’d pay a lot more if you wanted to rent a private old American car…