From Bovec take the 203 to Kranjska Gora. This takes you over the Vrsic Pass, the highest pass in Slovenia. After Kranjska follow the SS54 which will take you into Italy and then take the Predil Pass back into Slovenia. After the Predil Pass follow the 203 for about a mile and then turn left onto the 902. Although this road is a dead end the scenery is excellent. Return to the 203 and follow it back to Bovec.
I'd recommend visiting Logarska Dolina. Good accommodation there at the Pension Kmecka Hisa Ojstrica.
Consider visiting Tolminska Korita (Tolmin Gorge), Slap Savica (Savica Waterfall) and the Skocjan Caves.
