I’ve travelled along sections of the Nantes–Brest canal 4 times now, always in high summer when it’s been great to escape from the hot sun and under the tree canopy of the canal.
The canal is wide (by comparison with English canals) the tow path is well maintained and for the most part should fine for a trailer.
A few of things to bear in mind:
The canal does not run all the way to Brest or to Nantes for that matter.
If you’re keen to cycle as much of the canal as possible starting in the west, it’s probably best to join the canal just south of Pleyben (near Chateaulin)
A nice route to there from Roscoff would be Roscoff-Plouenan-Guimiliau-St Rivoal-Brasparts-Pleyben.
Most of the canal route is surprising quiet, just the occasional walkers and local cyclists, except around Lac du Guerledan which is a family holiday area.
There are a few old lock keeper cottages which turn into makeshift cafes for the summer but it’s advisable to carry some basic food and drink so as to avoid having to head off the canal in search of provisions.
The canal is 365 km long and can get a bit tedious, you might actually start to miss hills and traffic! It’s worth considering adding a bit of road time in to the tour, between Lac du Guerledan and Pontivy perhaps.
If you don’t already have it try to pick up a copy of Wendy Mewes ‘The Nantes-Brest Canal’ a good guide guide for walkers and cyclists.
Bon Route
http://www.amazon.co...94840546&sr=1-2