Watch the video below and stop it at 14:03. I'd post the image, but forget where I got it from when making this video on another computer. BTW, if you like the organ I posted the other side of the album too. Nothing sounds like the awesome Thomas Californian spinets, especially when played by a master like the Late harry Wach.
A great tip for making a wire harness ( for low voltage signals, and non-shielded wires of course) is to get an old parallel printer cable and use an A/B box on each end with the male and female ports & A/B switch ( not necessary, but the boxes are nice and there are good lead lengths on the internal connections). Plus you could use the A/B creatively- send 'A' to the Yamaha's upper organ's pedal pc board, and the 'B' to a MIDI converter board ( the 13,25,or 32 pedal-to-MIDI kits are very inexpensive). Then with the flip of the A/B switch you can choose between your stock Yammy's Bass-or- MIDI Bass...plus you can couple other sounds with the bass using MIDI. Mount a box on the upper part of the organ, and another on the pedal board. Then just connect a printer cable between the two. You can also use Amphenol round sockets -male/female for the shielded cables. In fact if you use an 11-pin you could probably get by with two of these for the entire pedal,speakers etc., but the printer cable set-up is dirt cheap as surplus.
I just gave a neighbors teenage kids my Yamaha Electone B4cr. I was going to separate the top from the bottom myself since all that is below the key desk level was the speaker, the pedals, and the reverb springs. Since it had a metal rolltop cover it would have been an instant travel ready organ, but I decided since I don't travel anymore what's the point. I have a Farfisa FAST 4 for portable playing.
Check out the HOAX Hammond, you could always add the authentic Hammond tone wheel organ to your organ too.