No full sus bike when I was there. The area isn’t geared up for mtb as we know it. There are lots of routes which are tourist type routes using forest tracks, farm track and road taking you to all the local sightseeing spots. There are a few sports hire places for kayaking, white water rafting and paragliding that also do bikes which were basic v-brake hard tails. The maps are not very good compared to our OS ones. I just went exploring and ended up hiking a fair bit.
If you get the cable car to the top of the ????? mountain there are some good walks and cafés.
Swimming in the Lake is good. Nudist beaches on far side 😉
The best cafe/food is the cafe near the end of the road up by the camp site, past the hostel. Kayaking can be had from the hostel and there is a climbing area near there. Another good cafe is in the village over the bridge, tends to have local farmers and loggers drive up in their tractors for a couple of beers and pizza. Lasko dark on draught there 😀
Very quiet place but with lots to do. Probably won’t be many other Brits there.
Hotel food tends to be local produce, don’t expect too much from it. We enjoyed it but did here some grumbling from other Brits, fish, chips and mushy peas are not on the menu!!
We stayed in the hotel on the corner by the Lake twice: http://www.bohinj.si/alpinum/jezero/hotel_jezero_en.html Try learning some of the words for coffee, please, thanks etc, makes a huge difference to service. We were the first Scots to have been there apparently, reception staff chatted for ages. Most people in the area speak very good English.