The mast treatment isn't such a big deal people put all kinds of "stuff" on their masts without a problem--the important thing is whether the cracks go through too far and compromise the mast itself. You might take some pictures of it and send them to Jamie at http://www.thesquarerigger.com/
and ask for an opinion OR reference to a local surveyor who would be able to assess the condition of the wood spars as well as the rig. You may be pleasantly surprised about the condition of the actual wire if the owner has been religiously putting linseed oil mixture on the rigging. Common soup mix for the rigging includes linseed oil/paint/stockholm tar slush if it is parceled and served. The mix depends on the owner.
By the way, Jamie's Tahiti Ketch is for sale--it's up in the SFBay area and I don't know the condition or price.
Here is another one that is in exceedingly good shape and a good price here in San Diego Link
Yes it has a V berth and yes it's really small for a tall guy! But, character, character...
PS Just found Jamie's boat on Yachtworld too HERE