Slovenia Advice November 25th to December 5th

For what it's worth our experience in Slovenia was that one morning we drove from Salzburg, Austria to Lake Bled. We arrived late morning, wandered around, had lunch and then drove on to Ljubljana. We spent the night there and the next day we drove down into Croatia for a few days. Then we drove back to Piran for an afternoon/night before moving on to Italy. LB was beautiful and we wish we would have spent the night. We also highly enjoyed both Ljubljana and Piran and could have used a second night in both places - and all we really did was wander around and drop in interesting spots. All the driving was easy as was the parking situation in each location. BTW - when we were in Croatia we stayed in Rovinj. It's just down the coast from Piran and when comparing the two Rovinj was preferable because it's a bit nicer.

Hey!
It's worth a lot. Thank you very much for helping me out. I am a little surprised how hard it is to get first hand advice on Slovenia, so I'm extra appreciative. I googled Rovinj and you're right it looks absolutely lovely. I'll be going there for sure. I love Salzburg I'm certain you fell in love with that City. <3 Since I have the 25th to the 5th I'll be spending the most nights at Lake Bled and Ljubljana just trying to get the rest of the trip sorted.
Was it a problem to cross Country borders?

Also, I will be meeting my husband (he's a much better driver) and we'll take the 5th-31st to go to Croatia, Bosnia and Herzegovina, Montenegro, and Albania. Then we'll loop back up and fly home from LBU Slovenia airport.

I have driven much (not all) of your Itinerary 1 route, including Trieste and also Piran and into Croatia. Driving in Slovenia is very easy, although I can't speak for road conditions in November, as I was there in Sept/Oct. Although I had 2 passengers (non-drivers) with me, I would not hesitate to drive in Slovenia or Croatia by myself. The roads I traveled were well-marked and well-maintained.

I already had my rental in Ljubljana, but there is (was) an Avis counter in the Grand Hotel Union Business, which is right in the tourist center. So you could either rent there or at the airport.

Lipica was a delightful way to spend a "slow and savor" afternoon. They offer guided tours where you learn about their training and breeding programs and get to visit some of the horses in their stalls; visitors can view practices (not daily, check schedules); and you are free to wander the extensive grounds as long as you like, admiring the horses as you stroll.

Driving in Trieste was also easy. The only "difficulty" in driving between Trieste and Slovenia was knowing that we had left one country and entered another. On the little road we used (on our way to Lipica) the only indication we had entered Slovenia might have been a sign, if that.

Be sure to get your Slovenian "vignette" for driving on Slovenian roads, as the fines are steep. A Slovenian rental should come with a vignette; my Croatian rental did not but it was easy to purchase online (with thanks to details from the Rick Steves guidebook.)

Happy to help! No problems with borders except the crossing from Slovenia into Croatia took about a hour due to the line of traffic (Saturday in July 2017).