Thank all of you for your help and advice. I reformatted the player (using the function contained in the original firmware) and reformatted the sd card with the Panasonic application. I loaded on 2103 songs, have approx 3 gb free in main memory and about 150mb free on the 16gb card. I re-mp3 tag'd all the files.
it refreshed in almost exactly three (3) minutes!
I am still looking forward to a better rockbox build that avoids the refresh of the O/F altogether, but 3 minutes is entirely reasonable.