Haven't been to Calais but spent a few nights in Le Havre. I quite liked it and everything was very central. Can't remember how far away the ferry terminal was from the city but I don't remember a long trek or taxi ride. Lots of shops and some really good restaurants. A very pretty park area but if I remember correctly we were chastised for sitting on the grass. Bench only, apparently. Yeah, I'd say it's a nice little getaway place for a few days. Have fun wherever you end up!