Itinerary help please - choose or do it all?

My family of four (two girls 8 and 10) are renting a car in Istria and doing a loop up and through Slovenia and back down to Pula to fly out. We love nature, walking around sites, kayaking/swimming, etc. We like to walk to restaurants. I have about 5 or 6 nights total and don't want to move constantly. Ideally one base or two. I'd like to see Postojna Caves on the way to Ljubljana and am debating whether to stay there or keep going up to Bled or Bohinj. I found a lovely apartment in Bohinj but have heard it's not a great base because it's off the beaten path from Bled etc. Or would that be good to stay there (we don't need nightlife with kids and love to hike and walk and there are a few restaurants walking distance from the apartment I found) - or Should we go straight to Bled for three nights, then do the Julian Alps and over to Soca Valley and stay in Bovec or close for thee nights? Or I could break it up to four and two nights? The drive back to Pula is over three hours from there and appears to go through Italy as well. Is this a good idea or is it too much and should I choose between Soca and the Bled/Bohinj area? Is an afternoon in Ljubljana enough or do we need a night there? The other option is to base in Ljubljana instead of bled and do day trips up to Bled, etc. Or could I hit it on the way up and somehow loop back through it on the way back down to Istria? We will be heading up from Istria most likely from Opatija. My last thought is that the wine tasting area may be a good break up for the trip or can that be done from Bled or Ljubljana as driving after wine tasting back down to Istria is probably not a fabulous idea! Thank you for any help - I"m really struggling with this itinerary and have heard amazing things about Soca and have seen some insane photos so hate to miss it, but also don't want to stress ourselves with constant moving with two children and packing/unpacking. Any help would be greatly appreciated!