One thing to beware of in France is the "bus section".
A number of years ago I did a circular trip Gare de Lyon - Nevers - Saincaize - Vierzon - Les Aubrais - Orleans - Austerlitz.
( not sure I've got Saincaize - Vierzon the right way round - atlas is at home, so please excuse any geographical errors in the below... )
The first leg to Nevers was a non stop Corail hauled by a Sybic ( Class BB26000 ). The second leg was a Caravelle DMU. Upon arrival at Saincaize, where the Caravelle either terminated or went onto a different route*, the official connection to Vierzon was a bus.
However, I stayed put and waited for the next train, which duly turned up as a Corail hauled by double headed BB67000 diesels. Needless to say, this train arrived at Vierzon about ¾ hour ahead of the bus!
This meant I could catch a connecting train to Les Aubrais and Orleans formed of a Z5100 EMU, my nex moves were another Z5100 back to Les aubrais for a Z6500 hauled Corail to Austerlitz.
The point is, had I just followed the sheep onto the bus, the trip would have taken much, much, longer - so it is always worth checking whether there is in fact a train before allowing yourself to be forced onto a bus.
* I really must dig out my old notes!