Hi, why not check out both countries? It's very easy from the city of Maastricht, Lanaken, Belgium is about 10kms away.
You can even throw in a day ride to Germany if you like, Aachen, Germany is only 30kms away, with a streight road and a bicycle path next to it.
The hills also begin just south of Maastricht so it you like flat fine, but if you like a little more its only a few kms away.
As for how to get here, well there is (new) regular train service from Brussels international airport to Maastricht, only one hour. You can yahoo or google it, also about the bikes.
Photos of all places could be found at flickr.com
Hope this helps some
cheers