Make sure
Bike
You have originals of all Docs with you
That your Ins covers you abroad
Break down Ins and travel Ins recommended
waterproofs or good gear that can handle wet weather
Sat nav or basic maps at least and keep a note of where your going
Do a full check up of bike a good few days before you go (gives you time to sort if needed)
Make sure you have good tyres on as German cops don't like worn tyres
Money
Tell banks you'll be using cards abroad (if needed)
Carry Euros and keep them somewhere safe
Fuel
Most motorways have pay for use pumps so u can use cards if u wish
Prices for fuel is pretty much same as here (just looks more because it's in euros)
Clothing
I take 1 pair of socks, pants and a t shirt for each day
usually 1 or two pairs of trousers for evenings depending on length of stay
1 pair of shoes for walking/evenings
On the road
Best place to be in a group if your unsure is as close to guide as u canwhen riding ride to the rear left or right of the bike in front as this keeps your view clear and safer if braking is neededDon't leave a huge gap between you and rider in front as you'll end up with a car in it, this then makes you further and further back and possibility of getting left.
Finally biggest rule of biking in a group.... Have fun, take it easy and nothing is a problem that can't be solved.
Just a few thoughts sure their will be more but if there is a problem next week or you need help you come see me and jobs a good un