I did Nice > Calais on motorail in 2003. Bloody excellent it was too, if a tad pricey. However, if you add it all up it worked out as not much more than an overnight stop, loads of petrol, tyre wear, tolls, plus the coolness of having an extra day riding nice roads in the Alps rather than slogging up an endless autoroute.
There were a few of us. We had twin berth "couchettes" to sleep in which were comfy enough but smelt a bit due to sweat-soaked leathers festering in a pile on the floor.
There was no food or drink on board. Take your own. We did.
Bikes go on the last carriage and are last to load and oddly last to unload. Communications from the train company are poor so you can end up waiting around quite a while. The carriages are double-decked so keep your head down when loading.
Bikes are tied down by guys that have done it millions of times before.
End result is very secure.
If I was going to the south of France again, I'd definitely ride down (more fun when the holiday is still to come) and get the train back up. Nice to Calais was an overnighter and was very smooth, lots of nice sleep after some vin rouge and nibbles, and appeared as if by magic in Calais at 8am thoroughly refreshed.
Strangely we were all ushered into a breakfast place in the train yard in Calais where you had to have breakfast otherwise you seemed to get into trouble. Whilst this was happening they unhooked the train so the unloading could start. Bikes off last, poor communication about what to do and when from the "operatives" so we hung about until we got the nod, then it was off to the chunnel and away. Sorted.
