MIDI suggestions?

Hi all. I've got a Radio Shack LK-1261 and a USB midi adapter, and it seems
to show up correctly. I've looked at Debian and the software stack is a bit
perplexing, and I'd like to drive it on FreeBSD.

My goal is to be able to use the keyboard to input notes and then be able
to normalize and manipulate the data in something computer-side, and then
ideally send the results back through the keyboard to play using the
keyboard's built-in voices/instruments and one way or the other (keyboard
involved or not) render finished pieces into WAV or FLAC or something I can
use in still other tools.

The model I have in my head is based on an old Mac program called "Studio
Session" which gave me a score to fill out, with each staff being a voice
or instrument. With Studio Session I had to click in notes with the mouse,
and I'd ideally like to be able to streamline that by being able to play
bits of things on the MIDI keyboard to capture them.

That said, I'm a little confused about where to go from here. My
understanding is that I need some sort of Digital Audio Workstation and I
see references to jackd for pointing different pieces to each other in
various directions, but my initial poking around hasn't gotten me to where
I see notes pop up in a score or piano roll in anything, nor have I been
able to take a midi file from the 'Net and dump it into the keyboard. The
furthest I've gotten was some debugging tool that showed when I'd change
"programs" (voices/instruments) on the keyboard and noted keypresses and
durations, which suggests that the connection I essentially want is
working.

Thanks in advance to pointers. As always, if we figure this out and there
isn't a decent set of newbie documentation, I'll be happy to write up
introductory documentation as thanks for the assistance.

-- 
Mason Loring Bliss  ((   If I have not seen as far as others, it is because
 mason@blisses.org   ))   giants were standing on my shoulders. - Hal Abelson