Buses are available for transportation to where you would like to begin hiking or to pick you up after you have finished your excursions along the valley. Buses run daily between Bovec and Kranjska gora during June,July, August and September. Timetable of buses ara available here.
Motorail trains operate on the line between Bohinjska Bistrica, Podbrdo and Most na Soči, and run through the longest Slovenian rail tunnel, the Bohinj tunnel, connecting Upper Carniola in the North of Slovenia with the seaside Littoral in the South West. Motorail trains can carry cars, vans, pickups, and camper vans which don't exceed 3m in height and 2.4m in width. More informations and schedule you can find here.
From Kranjska Gora over Vršič pass, which is the highest mountain pass in Slovenia. In case that Vršič pass is closed because of snow, you can use bypass which leads through Rateče border crossing with Italy, passing the Tarvisio. Follow the road signs for Predel and Slovenia. Road leads back to Slovenia at the Predil mountain pass, where it descends towards Log pod Mangartom. On the crossroad just before Bovec, turn left to the Trenta valley. Bypass over Predil is half an hour longer than crossing the Vršič mountain pass.
Infront of the center.