Hi,
I think that some of the roads have now been re-numbered partly due to the EEC road numbering system and partly due to the toll road being finished and the old 138 route no longer an N class road.
However, the 138 route more or less follows the toll road but as a lot of the towns now have bypasses / ring roads locating this one cafe could be a bit hit and miss. There are several places that you could stop en-route though, try Bernay or Sees as both are fairly large and both should have a choice of roadside cafes.
If I can locate my "old" map I might be able to list the towns you need to pass through.
S