Visiting Bohemian Switzerland without a car?

I didn't even know there was a Bohemian Switzerland until I read your post, but in 2012 I traveled from Prague to Bad Schandau in the Saxon Switzerland, which is a Nat. Park in Germany, adjacent to the Czech N.P. I was able to get to Bad Schandau on the EC that runs on an every two hour schedule between Prague and Berlin via Dresden.

I see that that EC goes along the Elbe from Prague to Decin, where it enters the Bohemian Switzerland park. It takes an hour and a half to get to Decin from Prague. The EC doesn't make any more stops in Czechia, but at Decin you can switch to an RB which goes along the Elbe and makes 5 stops in towns in the park in the next 15 minutes before going into Germany and ending in Schöna.

I don't know what transportation options there might be within the park. In the Saxon Switzerland, I was able to travel along the Elbe on regional trains and there were buses from the towns that train stopped at to other sites I wanted to see.

I did this tour (https://www.viator.com/tours/Dresden/Best-of-Bohemian-and-Saxon-Switzerland-National-Park-Day-Trip-from-Dresden/d22375-63545P2) from Dresden in 2019. It was excellent, except that our guide seemed to know very little about what we were seeing. The company offered me a partial refund when I shared this feedback with them, and I imagine they are now doing a better job of vetting their guides.

There were several of us from Dresden, and at the first stop we were joined by another group that came from Prague. There were seven of us altogether. So if you'd rather do it from Prague, you can probably find it on Viator (or try to figure out the provider and book with them directly).

First of all you need to make your way by train to Děčín. Then it's two options:

OPTION 1: From Děčín, take the 434 bus until it gets to Mezni Louka (35 minute trip) and then use Gabrielas Trail to walk back 3km to Pravčicka Gate (hikers route, beautiful scenery). You arrive at the Pravčicka Gate level. To get down to the road you either keep on Gabrielas Trail or you take the chair lift and when you get to the road turn right and it’s 400m to the bus stop.

OPTION 2: From Děčín, take the 434 bus and get off at the Pravčicka Gate bus stop (30 minute trip). From here you can hike Gabrielas Trail (30 minutes) up to the gate. Alternatively, from the bus stop, if you walk 400 metres in the direction of Mezni Louka i.e. keep walking along the road, you’ll walk past what looks like a mini water tower on your right. Next on the left is a track. 300 metres along the track on the left you can take the chair lift up to the Pravčicka Gate.

Allow 1.5hrs for the train and 30 mins for the bus. Bus timetables at https://www.ceskesvycarsko.cz/cs/dopravni-spojeni/linka/turisticky-autobus-podel-np-linka-c-434-decin-hrensko-mezni-louka