The first thing that comes to mind here is what do you intend on doing with the mod section when it’s in “portable mode?”
The instrument won’t play without the mod section hooked up.
While there is a way to make a pre-wired plug that inserts into the 12 pin connector normally used for the mod section, you’d obviously lose some functionality with no pitch or mod wheels.
The MIDI to CV converter would have to generate both pitchbend and modulation signals (and likely then only vibrato, not true OSC to OSC modulation.)
So you’re going to experience some loss of functionality or sound possibilities.
The loss of the glide on/off switch is no huge thing. Simply turn the glide knob all the way down.
But the release switch normally affects both envelope generators’ release sections, so it might be frustrating having to manipulate both release knobs as you’d like AND the glide knob per patch.
Perhaps make a housing for the mod section?
It could also contain a CV and Gate input jack for the MIDI to CV converter or an entire converter itself if large enough.
As for Midi and keyboards, you can leave off the keyboard and use a custom cable that plugs into the six pin keyboard connector.
This would be the same connector you’d normally plug your stock keyboard or OptoKey connector plug into.
That connector accepts both a control voltage and a standard V gate. (not an S-trig.)
The greater problem is that you’d have to transpose most MIDI to CV converters because the Minimoog is based in the key of F, not C like most synths.
You can try using the rear panel S-trig in jack and OSC CV Input jack, but you’ll lose glide because that OSC Input jack doesn’t go through the glide circuit.
(Some MIDI to CV converters offer glide, but they don’t always sound like a true Minimoog glide.)
Also, the S-trig input jack only triggers the envelopes, not the keyboard CV memory circuit.
So whatever MIDI to CV converter you use must be very accurate and also hold its CV output stable even when there’s no note played.
If you plan on using the S-trig input jack, the MIDI to CV converter must also be able to generate an S-trig.
Some only generate V-trigs (a gate.)
I know it’s a lot of money, but perhaps buy another model D just for touring?
It’s a lot of work to change over from one “mode” to another.
If you’re going on tour for months at a time, it might make sense.
But if you’re planning on going back and forth between studio and stage every few days or weeks, changing everything over and back again is going to get real old, real quickly.
Screws, connectors and probably recalibration are going to need attention every time things are swapped.
Fwiw, an optokey does not need a keyboard to operate as a simple MIDI to CV converter.
You simply have to make sure it can hook up to four signals: + power, ground, gate in and CV in.
The main board does not need to be hooked up to the keyboard action or opto sensors in order for it to work.
You can just plug and unplug it as needed.
But it’s also not the world’s best MIDI to CV converter.
It can’t generate notes below low F or above high C and can’t produce modulation or pitchbend.
I can’t recommend anyone in NY to do the work, but I’m sure someone exists there that could do it.
But when you do find someone, make certain they understand everything first and can deliver a synth that won’t fall apart soon afterward or worse… on stage during a performance.
Perhaps ask Gene Stopp.
He works on KE’s Moogs and sometimes travels around as part of his normal day job or when on tour with Keith.
He also owns his own optokey-equipped Mini, so he already understands a lot of what’s needed to know.
I should also say that no matter how careful one is, the more one handles an instrument, the more chances there are of scratching things unintentionally.
Good luck!
