We're not talking about a CEV type vehicle.
An interstellar class vehicle will be massive, on the order of many thousands of tons, to protect the crew from radiation. Think of a vessel in the weight class of ships like Bismarck, Missouri, Yamato, or maybe even a modern day carrier. Then it would have powerful magnetic shielding on top of the thick physical hull plating and bulkheads. The colonists hybernating deep in the bowels of the ship will not have to worry about radiation.