While you could rush around Slovenia and cover it quite extensively in just a few days, I recommend you take things easy and soak up this tiny country's myriad pleasures. Relax in and around its many pleasure spots and enjoy the possibility of adventures both hard and soft. Bear in mind that there are tolls on all highways; these are clearly marked and you can pay with a credit card.
Day 1: Arrive & Head East
Pick up a prebooked rental from Ljubljana's international airport, and head east, to the salubrious town of Maribor, where you can stroll through gorgeous squares, lunch at excellent restaurants, explore a vast underground cellar, and enjoy a sundowner at the legendary waterfront area known as Lent. In summer, you may catch some of the excellent entertainment that forms part of the Lent Festival.
Day 2: Ptuj, Then the Jeruzalem Wine Road or Otocek Castle
From Maribor, it's a short drive through gorgeous countryside to the ancient Roman city of Ptuj (pronounced pit-ooey), which you can explore in a few hours. Then head out to sample the fruits of the vine along the Jeruzalem Wine Road. Presuming you enjoy a liquid lunch, overnight at one of the wine farms, where you can also enjoy a traditional farm dinner. Alternatively, skip Jeruzalem and head south to the newly refurbished Otocek Castle where you can live out a royal fantasy, dining in its beautiful courtyard, sampling the famous local wine, Cvicek, and then bedding down in the castle's luxurious quarters.
Day 3: The Lakes
Strike out early back toward Ljubljana, but head instead to Bled, some 31 miles (50km) north; you should arrive well before lunch. Book a suite at Vila Bled; you can use the spa at sister hotel Grand Toplice, sunbathe on the private lido, or take one of the private boats and row yourself to Bled Island, where you can explore the lovely church. Take a relaxed stroll around the lake and drive or walk to the thousand-year-old castle perched above the water, before setting off to explore Lake Bohinj.
Days 4-5: Soca River Valley
If you're feeling adventurous, start your day by swimming out to the island and back. After breakfast set off north to the adventure resort of Kranjska Gora, which marks the starting point for the route over the Vrsic Pass in the Julian Alps. You'll negotiate 50 hair-raising switchbacks in just 25km (16 miles) before reaching the other side -- the Soca River Valley. You can indulge your spirit for adventure in Bovec (the best base for skiing on the slopes of the Kanin), but reserve accommodations near Kobarid -- either at Casa Hisa Franko (which also offers the most exciting restaurant menu in the country), or at nearby Nebesa, perhaps the most idyllic getaway in Europe. In Kobarid, visit the antiwar museum, and grab a map for the outdoor walking "museums" that you can undertake under your own steam, preferably in the early morning, before temperatures start to rise. Spend your second day white-water rafting and attending to other river- or mountain-bound adventures. At Hisa Franko, ask for a lunch basket and picnic on the banks of the nearby river.
Day 6: Piran
From the Soca Valley, it's a 2-hour drive toward the Istrian Coast, connecting with the main highway heading south. En route, stop at the Skocjan Caves, which are a scintillating 2-hour diversion. In Piran, take your time exploring the cobblestone streets and back alleys, cooling yourself in the refreshing waters of the Adriatic before settling in for an evening of seafood at Neptun. If you feel you're up for a party, head over to the nearby resort town of Portoroz where you'll find casinos, nightclubs, and merry-making crowds.
Days 7-8: Ljubljana
The highway leads directly from Piran to the capital; set out after an early-morning swim. Ljubljana has great charm and can be extensively explored on foot or bicycle. Head up to the castle for a good look at the layout of city, then explore Old Town, where you'll find plenty of stunning restaurants. In the afternoon, prioritize the art museums, but be sure to grab a seat at one of the lively cafe-bars lining the Ljubljanica River for sundowners. In summer, try to catch a festival performance at the Krizanke Summer Theater, perhaps after an early dinner at AS. If you have the energy, prepare for a night of clubbing, or try to visit a selection of the city's best watering holes.