Deauville
Rollerskating on the beach... At only 200 Km of Paris, Deauville beach with its "promenade des planches" (wood path above the sand) is a good idea, but only if you have no roller in-line.
Indeed, the wooden boards are in the axis of circulation and you can block your wheels between two boards if you have some in-line rollers skate.
The ground is very sweet in the town, especially the road near the beach.
If you are courageous and if dirty ground for 100 meters doesn't bother you, try to cross the "Pont des belges" bridge and go to Trouville. It's almost the same but the atmosphere is less snobbish...
Annecy
A very good souvenir: a wonderfull cycle track, 10 Km long, border the Annecy lake, without cars. And to cool down you can dive headfirst in the lake: swing beetween mountains is inusual (for me it was). You can rent rollers in Annecy.
New-York
I just do roller skate in central park. Many bicycles there, but also joggers and roller skaters. The park is huge, around 1 Km by 6 Km. The ground is a bit rough, strong arch massage, but your lungs will enjoy !