The land is table top flat, with a few ditches running about. There is limited coastal access and what coast is accessible has no dunes.
To build another course would realistically leave two options:
a new course similar is style to TOC, with great subtle movement, or
try to use a new course in conjunction with the existing course, creating two layouts that would weave from the flat areas to the dunes, sort of like Spyglass. Personally wouldn't like this option, but it could be done.