Janet,

You need to come up with a plan based on the curerent condition of the
cottage. How well is it insulated right now? Ceilings? Walls? Have you
checked for wind leaks and caulked them? How are the windows and doors? Do
you have storm windows and storm doors?
I'd install some masonry around the cottage periphery, enclose the crawl
space, insulate it and then remove the floor insulation..
What's a bush cord of wood? I've never heard the term. When does Winter
start where you live? There are lots of books on insulating housing so head
for the library.

Dave M.