Norway
Haven't done the World of BMW tour, but did go independantly (with pillion) for a month to Norway last June. Petrol was expensive (between 85p and £1 per litre) but then so was everything else except alcohol - which was extremely expensive and virtually unobtainable. Bearing in mind the cost of Norway, I didn't feel the trip was too expensively priced, what worried me was that they seemed to spend time in restaurants and bars and that would have proved VERY expensive.
Having said that, unless you camp and cook for yourself (and maybe take food with you - as we did) then allow a lot of money for eating in restaurants.
The cabins are in (almost) every campsite - some sites are cabin only. A couple of Norwegian organisations will send you a map showing all the sites, along with approximate costs and facilities (the latter info can be extraordinarily inaccurate, and the prices for a Motorcycle can vary from between just more than a pedal cycle to more than a car and three adults). If you want more info on how to get these maps, let me know.
Generally planning a trip yourself should be pretty easy, there aren't that many roads to chose from. Nor many destinations for that matter and the Rough Guide is pretty good.
If you do decide to 'do it yourself' feel free to ask for help as there are several people on this board who have been (some many times), and at least one who lives there.