Hello! I am posting info from our trip in case it's helpful for anyone. There weren't too many posts about driving in Czechia that I could find before going. We stayed in Cesky Krumlov, Prague and Marianske Lazne.
We started at the Munich airport (our trip was bookended by work meetings there) and ended up choosing a road trip because short flights to other cities were very expensive and we are a family of four. A rental car for 8 days was less than $600. Czechia was not on my list of places to go, but I absolutely loved it. Slovenia has been on my list, but it was a little too far, and we had recently traveled around Munich and Salzburg, so that's how we decided where to go.
Driving from the airport was easy and we purchased the vignette for Czechia online while we were on the move ($35 for 8 days). We stopped at one gas station and they did not sell them and directed us online. It took a few tries and two different phones to make the purchase, so have some patience. We stopped in Passau for lunch. Parking lots/garages in Germany and Czechia were confusing at first - usually you need to pay before exiting and input your license plate.
The roads near the border became smaller and the scenery more beautiful. Parking in the lots in Cesky Krumlov was very easy. We schlepped our baggage to the hotel, but when we left they offered to shuttle us to our car, which was much better! We stayed at the Grand Hotel which has a perfect location. Cesky Krumlov is one of the most beautiful and charming towns I've ever seen. In the morning and evenings it was almost empty and even with the tour groups walking around, it was not overwhelming. We ate dinner on the main square and there were about 10 people in the square. One day we booked a raft with Malecek Rafting and floated down the Vltava. I highly recommend doing this (cash only for the raft). We ate extremely well, except the hotel breakfast was kind of gross.
On the way to Prague we stopped in Tabor for the afternoon, which was another charming and beautiful town. It is small so we just wandered, got a coffee and ended up going up the tower with a small museum. I don't think I would stay overnight here, but it was lovely.
Out hotel in Prague was very central in Old Town and we did some research about parking elsewhere, but did not find a solution that was cost and time efficient, so we drove straight to the hotel and paid a ridiculous parking fee. Driving in the city wasn't that bad, but I also would have preferred to avoid it. We spent three nights in Prague and obviously loved it. I won't get into the itinerary as there is lots of info about what to do there.
I had bookmarked a few different places to hike north and northwest of Prague, but a heat wave hit and we had to skip all of that. The landscape was incredibly pretty and I feel like we really missed out. So we drove to Karlovy Vary for the day. We snagged parking at the Grand Hotel Pupp (I really wanted to stay there but it was 100% booked when I was planning). We strolled around the town, had lunch and of course bought a cup to sample the mineral water. It is yet another stunning town - very different from Cesky Krumlov. I think if we had stayed here I would have wanted to go on hikes/walks as it had almost a mountainy feel. We continued on to Marianske Lazne because that's where I could get a hotel room. This town has a gigantic park and is pretty, but there is not much to do and it's fairly sleepy. We went to a colonnade and had a really great dinner (Česká hospůdka). I recommend getting Oblaten spa wafers here or in Karlovy Vary. They are delicious!
We all loved Czechia and now seeing the rest of the country is on my list! Driving was easy and parking was plentiful, but always a walk from town. And we definitely needed cash everywhere outside of Prague.