Driving through France............

You could do Nancy to Mulhouse direct - but still the same problem [if that is what it is] of going over the mountains - but to me that is a very interesting part of the trip, and a nice break from motorway/dal carriage way drivingThe Colmar direct route is the shortest - its about 25 miles further via Strasburg, and 20 direct to Mulhouse, but the timings are about the same.  I do think that you save a little fuel on the Colmar direct route - but its probably not a great deal Flashed by a speed camera in france?  See;-http://www.thelocal.fr/20130530/france-cracks-down-on-speeding-foreign-driversYou might be lucky - opinions differ on how good the French are at getting the fines paid [Google it]

Route from Nancy is E23/N57 to Remiremont then E512 to Mulhouse - a delightful run, but I think the Nancy/Colmar direct route is easier [Doing it at the end of October - Calais to Mons [1st overnight stop] then on to Colmar [2nd stop, in Mercure in Town centre] - then on to Lake Maggiore area for a10 days before returning via Pontarlier and St Quentin [using french toll roads]

"............  is this the famous alternative epinal route many do as an alternative?  ..........." Don't think so - the 'alternative' is probably the route passing near Lorrach, that by-passes Basel

Using toll route for variety.  We've been driving down 2 or 3 times a year for the last 10 years, so occassionally we like a changeAlso, now we have a dog, we do shorter 'hops' [3 overnight stops], and are seeing if this route is OK for avoiding an overnight stop in Switzerland  [No dog this time]