We did Dudley to Bologna which is about 1000 miles in 5 days, which was a fairly leisurely pace.
Dudley - Valenciennes via the tunnel 350 miles - all motorway :
Valenciennes - Epinal 260 miles - mostly N & D roads
Epinal - Spiez 180 miles - Mostly A roads
Spiez - Lecco - 190 miles - Via Susten Pass, all A roads but we would have been better off jumping on some of the Swizz Motorways to avoid towns etc
Lecco - Bologna - 170 miles - Half & half, busy roads.....
On the way back we did:
Misano - Somewhere in the Dolomites (lovely) 220 miles - A roads
Somewhere in the Dolomites - Bregenz 260 miles Half & half
Bregenz - Top of the Black Forrest via A500 180 miles
Top of the Black Forrest - Luxembourg City (don't bother) 190 miles Half & half
Luxembourg - Ypres 200 miles Half & half
I wuld prefer to take my time and see some places.
This time we will probably do it in 4 days, which is about right I think, any less and it's just all motorway or very long days......
Don't try to do Switzerland or Austria without a Vignette!
We booked all the hotels as there were 4 of us, and my wife would have shouted at me if we ended up riding around trying to find hotels after 6 hours of riding in the rain!
Some of the others just found places as they went, which is easier for just 2 people etc?
The best thing to do is find some nice roads, then use motorways to avoid towns and boring busy stretches of road