We have an overnight in Paris before getting to Eurotunnel for check-in about 5pm the next afternoon; hotel is in the NW at La Courneuve, with a choice of RER or Metro to get in and out of the city, & approx 2.5-3hrs to Calais, so we'll need to be back there for about 1.30-2pm.
Our intention is to leave the hotel at about 8am so we'll have 5 hours max to travel in, travel back out, & see stuff - not long I know! - suggestions please? (Would one of those open-topped tour buses be the best idea?)(Assuming it's not raining...)
Also, would the RER (500yds from hotel) or Metro (about a mile) be quickest/most frequent?
TIA