Just 40 minutes far from Rome I suggest 2 comfortable areas to reach by train starting from Termini Station. These are MACCARESE and LADISPOLI. MACCARESE has good and quite baches to visit and a lot of point where Windsurfer meet.
LADISPOLI instead is very famous for it’s Black-beach reach of minerals of iron (ferrum). In Ladispoli you will find a lot of Restaurants along the beachside where it’s possible to taste the latium fish specialities.Moreover in Ladispoli it’s possible to stay in the famous hotel of POSTA VECCHIA ( http://www.lapostavecchia.com) located just in front of the sea above romans pools.
From Ladispoli and Maccarese trains run for these cities and back to Rome every 30 minutes.