printed map for driving in Slovenia?

I used a combination of Google Maps and rental car GPS in 2019. Google Maps was NOT always adequate. I did not use a printed map.

You can (and should) download a map to your phone prior to setting off on your drive.
With that and GPS, you should still be able to make your way even if you lose connectivity.

At the same time, intersections are well marked as to where the roads lead to, and there
are not that many options in the countryside anyways. So the chances of losing cell signal
when you need to make a turn is fairly low.

If you're a AAA member, you can order a free printed driving map. That's what I used as my backup option.

Thank you all! I am a AAA member and didn't even think about that option ... will get that!

I've also been worried about getting driving directions without a cellular connection. I like the idea of downloading the maps to your phone, but I worry about calculating new directions/routes without a cellular connection. I've had this happen before - get the "connection failed" error and then no driving directions from Google Maps on my phone. I think (but I'm not sure??) that Google Maps needs a connection for calculating the route, so downloading the map ahead of time wouldn't help you here.

My solution is way more wonky than printing out maps, and takes a lot of time to set up properly. But it does let you do everything on your phone in offline mode (still needs GPS for live tracking and turn-by-turn directions).

1. Install the app OsmAnd on your phone. This is a mapping/navigation app like Google Maps, but it can read and use .GPX files, which are like saved route directions. I don't think Google Maps, Waze, or any of the other more popular options can do this. There's a free version and a paid version with monthly, yearly, or lifetime prices. If I remember correctly, the only feature missing from the free version is that you can only download about 4 map regions at a time, which should probably be fine for whatever you have planned. I decided to spend $40 for the lifetime purchase because I found the app useful and wanted to support its development. . .

2. There are different ways to create .GPX direction files. Probably the easiest is to use Google Maps in a browser to create the route directions you want, and then copy the URL into the web service "Maps to GPX" https://mapstogpx.com/. There's another web service called "GPX Studio" https://gpx.studio/ which I really like for building routes from scratch - this can include hiking routes and bike paths that Google Maps can't navigate to.

3. After you have all the GPX files that you want, just download/transfer them to your phone. Within the OsmAnd app, you can import the GPX file as a "Track." This process was little non-intuitive for exactly where within the app to do this (OsmAnd is complicated and has a lots of functions), but there are instructions here: https://osmand.net/docs/user/personal/tracks/#import. Once you have the track imported, you can do Directions->Settings->Follow Track to set up navigation.

Additional notes-

There are other file formats for storing routes: KML and KMZ. OsmAnd can also use these. There is also a way to use "Google My Maps" and Google Earth to save KML and KMZ files, maybe in a way that could work on your phone for directions, but this actually seemed more complicated than what I describe above.

Hope this is useful to you or someone else reading this! :)

thank you Eli_va, this is great information! I am going to hang onto it for future trips with more driving; hoping this one will be relatively easy.

Nice, have a great trip!