Amiens

Yes, it is worth it! Great cathedral and some charming corners, plus the possibility of a boat tour in the Hortillonnages gardens when the season is suitable (not sure you'll find tours right now, although you can check).

Now this being said, I would pick Rouen, Reims, Troyes, Chartres, Le Mans above Amiens. Travelling times are similar for all of those, Reims and Le Mans can be more expensive because they require the TGV to get there.

Most definitely Amiens is worth seeing, culturally for its famous cathedral. Plus for historical reasons. I first did that day trip from Paris Nord to Amiens in 1989. Can't recommend where to stay in Amiens, only was there on day trips from Paris and Arras.