Hi Daryl,
Welcome to 5 Star and that's a GREAT question. Def not a "Newbie-Dumbest-Question-of-All-Time Scale." and there really are no dumb questions anyway.
I think I have seen some blogs or forum posts somewhere that talked about some solutions but since that issue doesnt affect me I didn't really pay attention.
Now here's a tool that may help alot in your situation, but AFTER you have picked some KW and just want to get an idea of US KW volume or compare popularity of a few different phrases.
Google Trends - Just just compared affiliate programs, affiliate marketing for a quick an easy example.
Then click below to only see US volume or any other country.
Google Trends: affiliate programs, affiliate marketing
Not sure that's exactly what you need but it may help.