This is a fabulous ride through rolling hills with great scenery. I did this on a road bike at an event organised by Specialized, although there were plenty of mountain bikes too. If you're using a mountain bike, I'd suggest road tyres, the hills are enough of a challenge without the extra friction of offroad tyres. We went clockwise from the starting point and stopped at a good restaurant for lunch after about 65 km - it's marked on the map. The start/end point is a restaurant that has public showers so you can bring a towel and a change of clothes and get cleaned up before a post ride beer or two. Thanks to Specialized for organising this great day out (and allowing non-Specialized bikes to participate), and special thanks to K Thana, K Eak and K Kake for inviting me along.
Here is a Google Earth image of the route -

The Google Map can be found
here.
Here are a couple of pics from this ride (not very good ones, I took them at the end of the day and the light was fading - the scenery was a lot better than this) -

