I'm an idiot. Though we're staying in 3e (nearest metro is Fille du Calvaire or Republique), I booked our 9:05am train to St. Brieuc to leave from Montparnasse. (I would die of happy to learn that actually Montparnasse was our only choice for a fast train to Brittany, but I suspect that I simply messed up and booked our tickets at the station furthest from us when Gare du Nord might have made more sense.)
The idea of either: a) lugging our huge suitcases around the metro at rush hour, or b) sitting in a taxi in traffic at rush hour makes me want to lie down and cry.
Gentle reader, how should we get from our hotel on rue Picardie to Montparnasse for a 9:05am train on a Tuesday morning in May without killing ourselves or each other? And how much time should we leave to navigate Montparnasse, which neither of us has ever been in?
Thanks in advance.