Hi Bolle,
Apologies for going off thread, but I loved your write up of touring though Austria/Germany, looking to do the same thing next spring. any tips/advise? 
Appreciate your help. 
We're sure busting thread integrity here but

*Look at when you want to. Late spring might be possible, but I believe early June is the earliest you should go without risking passes still being closed.
*If you can, be flexible in your planning, moving it a week forwards or backward according to weather. I had pretty lousy weather, the week before and after was beautiful. Remember, you're in the mountains, weather can vary quite a bit over the days/weeks. Check the webcams!
*I found accommodation no problem to arrange just showing up. But I was in early fall, in the summer it might be wise to book a bit in advance. There are quite a few nice guesthouses/hotels around which offer good, although not super luxurious, accommodation for around 40-50 EUR a night.
*I found it quite doable to do around 4-5 passes a day, including transfers (main roads) between them. That will fill your day quite nicely. If you're driving alone you'll be tired in a satisfied way at the end of the day!
*Enjoy your evenings, really nice after a day of driving to sit back and enjoy a good meal and glass/bottle of wine!
*Regarding the best passes, I more or less took the top-3 passes for each section as described on
www.alpineroads.com, and I was not disappointed! I would at least advice the Furka/Susten/Grimsel 'triangle', just amazing!!!
A few university friends are going on a rally/trip to the alps in two weeks, I'd love to join them but I couldn't manage to drum up a co-driver, and driving alone 5 days including driving there and back from the Netherlands might be a bit much. And I had already booked for the Goodwood Revival the same weekend.
But I'm sure going to go back, although I'm looking at driving in Wales with quite a bit of interest.