Probably the easiest way is to create a squirrel script, that expands every variable. Call this script before your need with the [[]] variable expansion...
The problem is, that variables have different values in different steps for example in compiling, so you would need a UI where you can set the build state....
So the easiest way is to create a squirrel script
Create a script that logs all your requested variables. Something like this:
Log(_T("$(PROJECT_FILENAME) = " + ReplaceMacros(_T("$(PROJECT_FILENAME)")))
and call the script with
[[Require(_T("Path to test script file"))]]
on every place you want to know the variables...