Just got back from our 9 day trip, what worked so well for us this year was the flexibility pre-planned tours lack.
We had the first nights hotel booked, but not the second, day one was all motorway and regardless of weather we wanted it out of the way, day three we were meeting others so we had two days riding to do the bits in between, day two was much better than the weather forecast so we made great progress and stopped when we had enough.
This left us an easy day three, we therefore decided to run up a dead end valley on out list for later in the week as it was not much out of our way and the weather was perfect, we also took the decision to press on in the morning with minimal stopping so we could have out lunch at the lake at the end of this valley.
This flexibility is what I like, on a planned trip I would be doing the routes as laid out, stopping where told, taking excursions where planned, even with Hotels pre-booked you can alter your routes to suit how you feel and what the weather is doing.
We also had the bonus of meeting some old friends and making some new ones, but could pick and choose if we wanted to ride as a group, meet at a certain spot or do our own thing, as Mrs rasher was on her first trip we just did our own thing at our own pace and then joined the other for food and drink in the evening.
I suppose if totally solo I would be more inclined to join another group - but probably prefer to go with biking friends, or even meet similar minded folk from a forum like this to have the support of another rider (or more) but keep a bit more flexibility.
You could also just follow Wapping who seems to like herding GS's around Europe.
