I don't know if there is a decent guide for a good motorcycling route along the River Loire from Nantes to Saumur....about 120km distance. But I'll give you the route I take.
It's NOT fast ! A lot of it is restricted to 70kmph and even 30kmph going through villages. And of course from this Sunday, your max speed will only be 80kmph. Having said that, this is a route for heads up, check the scenery, see bits that very few others do and find great wee bars and restos.
This is real hidden France, kept for a select few. And of course, you could hardly get a better tool to do it on than a TDM ! You'll need good, long travel, compliant suspension, effective brakes and an engine that has a broad power band.
Most of the roads are narrow and the surface is often crap ! The Tour de France has not been along here for years.....
There are many ways of following the course of the Loire inland. The fastest and most expensive is by using the Autoroutes A11 and A85 on the north side. Then there's the old Route de Paris the D723 and D347 again on the norths side. Slower, but no tolls.
So to actually travel along the bank of the Loire, you head for the south side. Come off the N844, Nantes Peripherique, at Exit 44 and aim yourself at the D751, signposted Routes Des Bords de Loire. This has you rolling on top of the levees.
[attachment=11135:Levee de la Divatte resize.jpg]
You can cross to the north at Oudon or Ancenis both of which have plenty of cafes, bars and restaurants
[attachment=11136:Bridge over the Loire at Ancenis.jpg]
[attachment=11137:Ancenis from South Bank of the Loire.jpg]
The next tricky bit is picking up the D210 in the village of le Pont de Vallee. Once you do follow it to Montjean-sur- Loire and cross the bridge to pick up the D210 on the north side.
There's another couple of sneaky manoeuvres which will let you avoid Angers and keep you on the river bank...more or less.
At the village of L'alleud, find the D111 and follow it east till you approach Bouchemaine then get onto the D112 which turns into the D4 at La Baudrairie then onto the D952 which will take you right on to Saumur itself.
[attachment=11138:TDM in Val de la Loire.jpg]
[attachment=11139:Traditional Loire working boat..jpg]
It's well worth continuing on this road and then crossing back to the south side just after Chouze-sur-Loire where you can ride past a genuine Nuclear Power Station. But I strongly recommend turning left after that onto the D7 and continuing to the village of Rigny-Usse where there is the perfect example of a Loire Chateau.
[attachment=11140:Rigny-Usse.JPG]
I must admit, I can get very easily museumed-out and I don't like spending lots of money on tawdry tourist traps. But this one is different, I promise ! The restaurant in the village is highly recommended, good food, not a lot of money, and ask for a pichet of house red !
So there you are, a nice gentle tour of a part of France that everyone's heard of but never experienced.
Right, to get back to Nantes, your choice is back to Saumur and take a blast along the A11 and A85 Autoroutes on the north or every bit as fast take the D960 and the N249 on the south which will get you back to where you started, exit 44 on the Nantes Peripherique.
The round trip is about 320km and riding time is about 5 or 6 hours.