Hi Anne,
You've certainly chosen a beautiful part of the world to visit!
For the past few years, my partner and I have been spending six months of each year in Slovenia, and the rest divided between two other countries. Last year was Pozzuoli (Italy) and Rijeka (Croatia). This year will be Belgrade (Serbia), Zagreb, and then back to Rijeka again, before going home to Slovenia in December.
Returning to Ljubljana from Rijeka involves my partner taking the 08:15 bus, and our car rental people meeting him at the bus drop-off point. After that, he drives back to Rijeka to collect me and our luggage!
Bus: http://bit.ly/1Sl0Y4p
06:30 - cost 45 kune (6 euros / 4.50 GBP / 7 USD)
08:15 - cost 95 kune (12 euros / 9 GBP / 14 USD)
Journey time - 2 hrs, 15 mins.
Car: our regular car hire firm is part of the Europecar franchise, and the staff are the most helpful people ever! You can either use their basic reservations email address: [email protected] or contact Lidija directly, which is what we do.
Lidija Podkrajšek - [email protected]
Do mention that Nicole and Kevin from Kašelj recommended them! We've been using their service since 2014, and cannot praise them highly enough. They will also collect the car from you, so you don't need to worry about navigating Ljubljana's buses when it's time to drop off the car (the buses are really easy anyway).
(I'm not in any way affiliated with them, by the way - I just think they deserve recognition for providing an outstanding service.)
If you have time, do try to fit in the Kamnik-Savinja Alps - they're beautiful... I see them every day from my kitchen window (unless our valley is covered in mist)! And if you take a wrong turning while driving up the mountains, you'll end up at Podolševa, which affords some spectacular views over the valley below. At the top is beautiful church, called Sveti Duh (Holy Spirit). If you decide to stop and take photos of the valley, if you're lucky, you may meet a lovely white mountain dog who'll want to make friends with you (he lives in one of the houses nearby)!
I have a few photos here: http://bit.ly/1Sl5ccf
*(I hope it's OK to post a link to my blog - I don't make any money from it, it's purely a hobby.)*
If you're going up into the Julian Alps, I assume you'll be driving up the Vršič Pass? If so, I wholeheartedly recommend stopping at Tonka's place for a bowl of jota or ričet (they're both just listed as 'stew', and which one you get depends on which one she's made that day!). The food is wonderful (there are other dishes on offer too, including puddings, or you could just have a coffee, wine, or local liqueur), the prices are exceptionally low (6 euros for stew with meat, 4 euros for the vegetarian version - enormous amounts of stew and copious quantities of bread!), and the surroundings are nothing short of fairytale! By the time you're here in Slovenia, Tonka's will be open daily (in the off-season, she's only open at weekends and public holidays).
http://bit.ly/22Kpn8r
(Again, no affiliations, just happy to recommend great stuff!)
Other places you might enjoy are Lake Bohinj (if you're going to Bled, Bohinj is only a few kilometres up the road - my personal favourite) and Slap Savica (a beautiful waterfall not far from Bohinj - do be warned though, that there are lots of steps to climb). Heading back toward Lju, just past Bled, there's a little slip road (on the left) to Pokljuka, where you can drive through some beautiful, tiny hamlets, and then head up to the plateau. The road up there is more wibbly-wobbly than Vršič, and a lot of fun!
I hope you have **the** most amazing holiday - be warned though, you'll fall in love, and won't want to leave!