That's a long run from anywhere in Suffolk. Up past Kings Lynn, Boston etc. Worth the trip though, Sutton on Sea is lovely.Why not pop up and see uncle Jim at Jasmine?
Felixstowe is worth a look. Peewit caravan site is at the docks end, 10 minutes walk from the sea front, and then you can walk through length of the prom which must be about 3 miles.
Only downside is that the docks work 24 x 7 and if they drop a container it makes a lot of noise.
There is a viewing point up at Land guard point, plus a nature reserve the old fort and a museum. All easily walkable. Choice of the Dooley or the Dolphin in easy walking distance.