Well I managed 650 miles from Denmark to Brugge on a Honda C90, my advice would be do a lot less than that doh

I'd kind of agree with consensus here that 250-350 miles a day will be a nice mileage, sustainable day on day, I'd be wary of Lorries and so forth trying to maintain momentum and forcing you into the hard shoulder when they pull in after an enthusiastic misjudged overtake and the fact you'll get stuck behind some of the slower movers without the oomph to get past safely

Part of me would like to repeat my Mongolia journey by something smaller like a wr250r, though I got great economy from the 990 at those speeds 52mpg average, by contrast my C90 got only 60-70mpg on the Autobahn.

If it was me, and I was concentrating my finances and time outside of Europe (taking the back roads across Europe could be fun, but taking the slow route costs £££) I'd tow/van my bike out to Chelm/Poland (I've driven that in 24hrs eating just my pack lunch from home) and head into the Ukraine on two wheels

Don't know if that is an option for you or not though, just throwing it out there....have fun

I'd guess your C90 was just that little bit slower than my B120 on the autobahn because I could (just) tuck in behind and benefit from their aerodynamics. You had to be doing about 50mph when they overtook to be able to stay behind them though. On the face of it it sounds dangerous but in reality being 70-80m behind a truck is a lot safer than having one 20m behind you - particularly riding a two stroke flat out.

I agree with you about overtaking though - I very quickly learnt not to (try to) overtake anything unless it was in a traffic jam.

Maria I think you'll be fine with those panniers your XRs are slimmer than my Derbi at the back and my Enduristan panniers are wider than the Andyz. In fact by the time I've packed the bags and put them over the homemade supports to stop them burning on the exhaust they're as wide as the handlebars, something I then completely forgot about on Hammersmith Bridge (sincere apologies to the Ford Fiesta owner).

If either of you fancy a ride out over the Downs do get in touch it's so rare to have the chance to ride with other 125's. I'll admit to having done a test ride on mine over that route with the luggage packed just to see what it felt like (answer:strangely top heavy).

Which does bring up another point perhaps and that's the difference in feel luggage makes to a lightweight bike. It makes sense because of course you're adding a much higher proportion of the bike's original weight. Mine feels quite light on the front end and seems to want to understeer when loaded and at speed which has resulted in the odd buttock clenching moment on sweeping A-roads.

Once you get used to it it's ok but if your bike feels strange I think that too can have an effect on your comfortable daily mileage.

PS. Are you going to be at the Muff Café this Saturday?

https://www.facebook.com/events/503369303117700/

Now e can't, we're going to visit friends near Plymouth this weekend so leaving Friday (with the car as we take the dog!)

For a ride we'll see. We are very busy now with paperwork and preparations. I need to get all the stuff on the (guest) bed and see how we are going to pack, what to take, and then do a test ride fully loaded. But not sure when yet ... hoping following weekend.
I'll let you know.