If you have time and go up the Henry Hudson Pkwy (if you want to go Merritt Pkway towards Milford CT and avoid a lousy part of 95), Wave Hill in Riverdale (NYC), just off the HHP, is a spectacular garden (
www.wavehill.org).
Prior to Mystic, after New Haven, Lenny's Fish Tale (Westbrook, CT is the one we go to) has fantastic food -amazing lobster roll, great fried clams & chowder). About 5 mins. off 95, we call ahead to order, we've been doing it so long ;-o
No great idea where to stop, we either stay at a relative's in NJ or a hotel in northern NJ near the Suffern, NY border (Ramsey/ Mahwah, NJ).