In CentrEd, is it possible to copy between maps (i.e. from Map2 to Map0)?
No, Use UOCopy.
Unfortunately I can't, as niether UOCopy nor RadMap Copy support custom map sizes. :(
Add this to "feature requests" I guess, as it would be a cool feature to have. For instance, it would be cool to be able to cut Tokuno Isle from Map 5 and then paste it back to Map 0 (or what have you).