cool, Pottsy! good luck with your trip, and i am glad to give you some info that could be useful... i wish someone told me these when i left for my trip.
yeah, the dolomites are fantastic, the heaven of bikers.
Also switzerland alps have some fantastic roads.
I travelled mainly on normal countryside roads, avoiding motorways, taking it easy, and managed to do an average 450 Miles (700 km) per day, in about 8 or even 10 hours.
Depends on your state of fitness, really; in my opinion, the seat and suspension are comfortable enough... but i stopped frequently.
The bike is not a road bike and because of the air-cooled engine, it's better let the engine breath quite often, especially in hot weather, otherwise it sucks too much oil.
On the way to padova (padua), I did 1200 Miles (1900 km) in three days, arrived there with a finished tyre, and had to top-up 1 liter of engine oil.
Yamaha dealers are pretty much everywhere in Europe, and in a couple of days I had a new tyre.
Dunno if it's just my bike (I'd like to hear from other TTRE owners about this), but I found that stretching the engine up and down the gorgeous Alpine roads consumes high quantity of engine oil.
On my way back to london I had with me some oil, for topping up.... and would advise you to have always some with you.
Fuel wise, in almost every european country you can choose between 95 oct. and 98 oct. petrol. I kept on 95 oct. one and did around 130 Miles (200 km) with a full tank, never had problems to find a petrol station, as soon as I was in reserve.
I had a Metalmule rear rack (metalmule.com), packed light, as you can see from the photos and it was more than enough for me.
Also from Metalmule, you can add the side racks, which are good for longer trips, or travelling with a passenger... i was considering those, in case my girlfriend wanted to come with me, but in the end she decided not to, as finds my bike too uncomfortable for her arse...
Next year I wanna go to Morocco and perhaps explore more in north Africa, but i am wondering to get a more touristic bike, like a BMW GS.... dilemma.
I am very fond of the simplicity of this TTRE tho... I love the air-cooled engines,
and seems there are not many bikes like that left.
Anyway... hope this helps your next european trip.
Cheers
Diego