The area around Bled is probably one of the most visited places in Slovenia. It's just about 50 km from Ljubljana, so easily done as a day trip, and it's also on the way to Kobarid, so it might make sense to do it as an extended stop en route.
The town of Bled is adjacent to Lake Bled, which is just about the size of Greenlake. In the middle of the lake is Slovenia's only island.
[caption id="" align="alignnone" width="848"] You can go by pletna boat and visit the little church.[/caption]
You can also walk around the lake, and you can climb up to the castle.
[caption id="attachment_1803" align="aligncenter" width="848"] Bled Castle[/caption]
And it seems a visit to Bled simply must include a taste of its renowned cream cake.
Nearby Bled is Vintgar Gorge.
[caption id="" align="alignnone" width="848"] Vintgar Gorge[/caption]
Also nearby is Bohinj. According to Lonely Planet:
Many visitors to Slovenia say they’ve never seen a more beautiful lake than Bled … that is, until they’ve seen Lake Bohinj, just 26km to the southwest. We’ll refrain from weighing in on Bled vs Bohinj debate other than to say we see their point. Admittedly, Bohinj lacks Bled’s glamour, but it’s less crowded and in many ways more authentic.
[caption id="" align="alignnone" width="848"] Lake Bohinj[/caption]
The more I think about all these places to see around Bled, the more I think it will be worth a full day and not just a stop on the way to Kobarid. But we will see how it goes.