Just watch eBay; Moulton's sell there from time to time. Very nice bikes.
Bikes are meant to be ridden; get out there and ride.
There are corrosion inhibitor sprays you can apply to the inside of the frame. You can also wrap the frame in corrosion inhibiting paper(treated with some oily type stuff) then plastic if you are just dead set against riding it.
Dave would tell you to ride the bike.