Hi Joe

Of the two options you've outlined, I'd definitely recommend the WBX instead of LF or Basic RX.  If you later decide to use the R-7000 you could hook up a hamitup or other converter.  (Note, you'll need to perform the R-7000 AGC mod).  With the WBX it will open up a lot of things in the spectrum that would otherwise pass you by, and the full stature of the USRP would otherwise be wasted on a narrowband source...

Max