Seems like these places that tend to get ignored would be pretty cost-effective in terms of getting delegates. That being said, the campaigns all must be aware of this, it is not like Puerto Rico just emerged from under the ocean a week ago. There is nothing secret about PR or its delegates. Romney knows about them, Gingrich knows about them, Perry knows about them, and Santorum may or may not know aobut them.
I do not know why the campaign would not put resources into these territories with little competition, but I guess that is a strategic decision on their part. This thread does not contain any super-secret info. The only question is whether there are enough RP supporters there who are willing to campaign for RP, and then see if they need anything from us, as a community, to make it happen.