barging and biking.....
My fiance and I rented a barge on the Canal du Midi (in Languedoc in Swestn France) for the first week of our honeymoon last October.....including two mountain bikes.....and it was really quite wonderful. We generally barged for 4-6 hours every day; stopped for 2-3 bike trips (to surrounding towns, along the canel, to vineyards and churchs and ruins) etc. Great food; decent wine; beautiful sights....very low key and relaxing (though we probably covered too much distance....from Castelnaudery to the Med..... I'd highly recommend it. It was nice have a bedroom, a kitchen, a bath/shower, and a decktop picnic table with umbrella that travelled with us. And the locks were much easier than I thought they'd be, even for just two people.
The Netherlands, though, may be a bit too densely (and roughly) populated for me....We rented our barge through Crown Blue lines (now Le Boat), which rents all over France, Belgium, Netherlands, Germany, Italy, Ireland, and England.....
Good luck!