Well, Ian, this sounds like a wonderful deal to me. It is often hard to locate a private party in advance to make camping arrangements, and this is just that sort of opportunity in a beautiful part of the world.
The Netherlands has a similar sort of thing in concept, but executed as part of a formal network in their "Natuurkampeerterreinen" campings network. These natural campsites range from repurposed old farms to mowed grassy fields, to old waterline defensive fort installations (complete with available tours of the fort interiors, near Schoonhoven). One of my all-time favorites was an old farm in Snelrewaard (Oudewater), shown here:
http://www.oude-boomgaard.nl/index-english.htmlPerhaps seeing some of these sorts of site will give your brother-in-law further ideas for how he might tailor the property for cycle-tourists. Having ready access to water and perhaps some sort of toilet facility would be terrific, as would a small gravel pad for placing campstoves to avoid setting summer-dried grass afire. A small trash barrel will go far toward making his life simpler. It really doesn't take much to make cycle-tourists happy (especially in such a picturesque setting), but a few small amenities might make his operation a bit easier as well. Please tell him "thanks" for giving this a go.
All the best,
Dan.
