90 pickup dicision time

hi there baught my first landy on monday got a 1996 300tdi defender 90 pickup i am after info/thaughts am after some way of keeping the back bone dry to put stuff in so was thinking of doing a rear cab conversion any ideas how easy this is and what i will need or if there is a eaiser way to make the back dry any responses would be great thanks alot dan

Canvas tilt, convert to hardtop or get a Ifor williams sheep pen.