I used to live in Ljubljana for about a year and then worked as an MTB guide for Jon at Ride Slovenia which is in a tiny village just north east of Kamnik.
I absolutely loved the place and the mountain biking is some of the best i’ve ever done, you’ve probably already guessed i’ve done quite a bit of riding there and would recommend getting in contact with Jon ad Ride Slovenia if you would like a guide, he does single days, a long weekend or a week. We sometimes had guests that stayed with us for the week and rode some days and went touristing others so might be worth asking him about that, although I think that might have been in lower season, worth a try anyway!
Regardless if you get in contact with him or not there are some great spots to visit in the area near Kamnik, Velika Planina has these fantastic old wooden farm huts all over it and great views (quite Lord Of The Ringsy), Logarska Dolina is an incredible lush green valley with a nice waterfall at the head of it and good access to hiking around Grintovec mountain!
In terms of areas to visit as a tourist I would really recommend the So?a valley, driving over the Vrši? pass is awesome and then the colour of the water down the So?a river is incredible and there are cool little gorges here and there, Bovec is a nice town to stop in on the way down. They have just been repairing the ski lifts and reopening the ski station here so it might be in use during the summer now too! Spent some time building this mountain refuge above Bovec two summers ago as well which you could go stay in which is fairly dramatic! There are quite a few of these around the country though. In general as others have said it is not soviet or ‘eastern European’ feeling at all, being bordered by several countries it has quite a lot of influences but the regions I was in felt quite like Austria and Italy and it really feels like everyone takes such good care of their own villages!
Here’s a couple little videos of some of the trails we rode in the Koroška valley…
https://anyexcusetoride.com/2017/06/28/slovenia-koroska-trails/
https://anyexcusetoride.com/2017/06/23/fresh-autumn-slovenian-singletrack/
BUT! Some of the best trails i’ve ridden in my life were around Ajdovs?ina!!! I’m afraid I don’t have any videos from that but my flippin god the trails there are good!!! If I find anything i’ll post up.
Hope that helps!