This year my parents came to visit, and as a special treat the wife's family took us for a drive up to Eigenji in Shiga.
Halfway up Mt. Zuiseki is a large collection of buildings that was once a thriving monastery where rainzai-zen was taught to over 2000 monks. It's still possible to receive zen lectures in the Kenshu-Dojo, even though it's mainly a tourist attraction now. The temple was built by Daimyo Sasaki Ujiyori, and he invited Jaku Shitsu to be the founder of the monastery.
The grounds are stunning. Absolutely beautiful in Autumn, Eigenji provides those really great pictures that we all crave for in our collections: the combination of maple leaves and temple buildings. Bonus moss covered monuments thrown in. They don't allow tripods in the grounds which is both a good and bad thing (my father was a little annoyed after carrying his all the way up there), so beware hard core photographers.
You can get Eigenji Soba up there too, full of mountain vegetable goodness.
If you're going by car, I reccomend a cruise up and down the Eigenji Dam, which is spotted all the way along with Japanese maples. One side of the river has an older road, not so heavily used and ideal for cruising speeds. Most places you can pull over and park, and even in the peak of the season on a weekend it's never bumper to bumper.
A seasonal reccomend!