Dale... I'm not sure about Suffolk... but if you don't mind tripping into Norfolk there's a few places worth seeing. Type the OS Map refs into the search field at multimap (http://www.multimap.com) to find locations.
There are four Iceni hillforts/camps (I know the idea of hillforts in Norfolk is a conflict in terms!) at Holkham (TF875443), Warham (TF944409), South Creak (TF848352), and Tasburgh (TM199960)... Holkham Camp is on 'No Access' land (...ahem) and is near to the wonderful Holkham Beach. Warham is really impressive... I was there only a couple of days ago n' it's fantastic! I think there's also a barrow cemetery nearby. Thetford Castle is built on an earlier Hillfort (TL875828).
Harpley Common Barrow Cemetery (TF755287), Salthouse Heath Barrow Cemetery (TG077423), Little Cressingham Barrow Cemetery nr Watton (TL861986). There's also 'Dead Man's Hill' near Thetford...but I have no map ref for this to hand.
There's an Iceni Village recreation at Cockley Cley which is open from April.
The area of South Norwich around Trowse seems to have a fair bit of history. There's the Henge at Arminghall (TG240060), flint mines at Whitlingham Lane (TG271078) and a walled Roman Village 'Venta Icenorum' at Caistor St Edmunds (TG230034).
Thanks to tip offs from Wideford, I'm gonna check out a possible 2nd Henge complex near Arminghall... and a couple of Barrows on Eaton Golf Course. Time to go shopping for a pair of plus fours!