Chrisch, the schlaf-im-stroh sounds really interesting, I saw that on a travel show here recently, but I fear that it would put a new twist on my wife's HAY fever! I'll think we'll be looking at basic hotels or hostels along the way as I don't think well be able to fit the tent etc onto the tandem.
From the schalf-im-stroh website:
If you are allergic
Straw is not hay!... Are you allergic, but still don't want to miss out on the farm adventure? Many farms cater for people with allergies by offering dormitories with mattresses, camping facilities or guest rooms.
I can also recommend the
Lago Lodge in Nidau (near Biel) to overnight, which also has a restaurant and brewery on site.
I've read that some of the routes are 'unsurfaced'. Are the conditions normally good? Good enough for road tyres?
Most of the unsurfaced sections are on hard packed gravel, and are very smooth to ride on. I'm on 700x35C tires and that has always been fine.