I've been playing around with computers and midi since the '80s. Also started programming back then, first in BASIC then FORTRAN and Assembly. When many of the engineers at that previous job started using C, I figured I may as well learn that one too. Its the only language I've used since. I have just an occasional use for programming at my current job now though. Do most of it at home learning 32 bit windows programming. I think the sane people are using C++. But C does everything I need it to do. Right now I'm concentrating on the graphics functions and drawing fractals.
(search internet for "Mandelbrot set")

Anyway my first midi setup was a Casio CZ5000 keyboard, Commodore64 computer and a DR T sequencer. Later I moved up to an Atari 520ST and MasterTracks sequencer. Mainly I play bass and just fool around with guitar and keyboards. So I had no way of playing anything into a sequence. Had to use event list editing and entering notes with the mouse. But I managed to put together some short good sounding sequences. Too much work though. Also wrote some software for editing and managing patches in the old DX7 keyboard. And now it's the PC and BIAB and PowerTracks

I've been using BIAB for working out chords to songs I was learning bass for. And printing out chord sheets. Trying to learn all the little things now to get a good sounding song going for playing some electric guitar and bass.

As oubla said above, the USB midi should work fine. Get that setup before you run BIAB.
Then when you run BIAB for the first time, you will get a window for setting up the midi input and output devices. You don't need a connection to a 5 pin midi device at all at that point. Just need the USB midi plugged in to the PC. The USB midi adaptor should appear in the lists of input and output devices. Then you just need to select it.
The instuctions for midiox should tell you exactly how to select the USB midi adaptor for it's use also. And again you don't need the GR-1 connected at that point.

If you know someone with one of those little Casio or Yamaha keyboards, many had midi outputs, and you could use that to test things before heading over to check out the GR-1. I would expect no problems though.