We are renting a car to drive through Croatia and Slovenia. Does the rental company include roadmaps or does anyone know good ones to purchase? We won't have access to a cellphone for GPS. Also, do we really need international drivers licences? Are there ATMs in the Dubrovnik arrivals area?
I have picked up rental cars without decent maps provided on several occasions. You can buy Michelin and other European map brands in travel stores here, or online, or in service stations and tourist shops there; see also http://www.ricksteves.com/travel-tips/transportation/navigate-european-roads. Although Dubrovnik Airport "only" mentions their Bank and Bureau de Change options, it's hard to imagine them not also having an ATM in the same area.
I've driven in Croatia and Slovenia a few times. The first time, in 2009, I was a bit nervous and bought a big, detailed map for my drive from Zagreb down to Dubrovnik (with stops at Plitvice and Mostar). But I really didn't need it at all.
On a trip to Slovenia a few years later, I didn't buy a map - I got a free one at the Ljubljana train station's Travel Information center. (When I asked at Sixt, the rental car office, they directed me to the TI center to pick up the map.) It was decent enough for basic navigation. I also printed out some Google Map routings between specific destinations. I never really got lost.
On my last trip in May, I brought my Garmin GPS with Europe maps microSD card. I was doing more off-the-beaten-path driving than on previous trips, and I'm glad I had it with me this time though it wasn't always accurate.
If you are doing something pretty simple - major roads, not many strange deviations from a standard tourist route - you can probably get by with a basic map you can get in Slovenia and Croatia, like I did. I found the signage for navigating fairly good, once I got used to it. It helps to do some research ahead of time of what towns are on your route (e.g. Google Maps is great for this.). You'll see signs directing you to towns on your route, more than big prominent road signs telling you what route you are on (except for the big highways). For example, if you are driving from Zagreb to Dubrovnik, it's nice to know that towns like Split and Zadar are on your route, so if you follow signs in that direction you are going the right way.
The nice thing about the roads out there is that your destination is usually very well marked on the highways/roads and there will be multiple signs pointing you to the correct turnoff.
I bought a Michelin map of Croatia (also Slovenia, Bosnia, Montenegro, Macedonia) at a local Barnes & Noble. It's very detailed. I wouldn't feel comfortable just going without a map. You can also print out place-to-place directions from viamichelin.com. I'm pretty sure we got kuna from an atm in the Dubrovnik airport and that there were several choices. There have been a couple of discussions on this forum about the IDP, just in the last couple of weeks. Do a search to see 40 or 50 responses. My advice is just get it.
There were a number of ATMS (4 or 5) in the small Dubrovnik airport right before you leave the building. I was there in May and got money to pay my airport shuttle.