Did this the other night (early Jan). Not a nice road in the dark, the corners come up quick. I have also done this during the day, be careful of the do gooders with their private speed camera through Grundisburgh and other villages in the locality.
Very nice rural road. Good surface. Lots of nice bends and a very long straight past Otley college (if doing this route from Woodbridge to Needham Market then beware of the very sharp corner at the end of this straight). Could be coupled with the A1120 route for a pleasant circuit of about an hour (Only downside would be the stretch of the A12 between Yoxford and Woodbridge).