Regarding the key issue...a good locksmith can either acquire or make you a key based on the mechanism/VIN. Been there, done that on a few bikes/vehicles. Sometimes you can go to the dealer and with proof of ownership you can order a new key. Not sure if SF Motorsports will do that, especially for a bike that old. Maybe if you buy a case of oil from them. HA HA It's also possible to bypass the switch if you have a wiring diagram and are good at "working on electronics." Sometimes there are perks of owning a "cheap" bike! I've actually installed a toggle switch on a few bikes, some as a key bypass, some as an extra security measure. It's fun when you forget about the toggle switch and try to figure out why your bike won't start though! LOL
Knowing the NM MVD it might be an uphill battle to get that thing titled, especially since it's got an out-of-state previous registration. I've had some success with the bill of sale when it was an old dirtbike and all I wanted was OH registration, but for putting it on the street it's gonna be a little more difficult.
The last time I knew of someone who bought a "lost title" vehicle, the
previous owner had to go to the MVD and file for a lost title replacement and THEN sign over the new title to the purchaser. And that was an in-state title. My guess would be she's gonna have to file for a lost title replacement from whatever state she has it registered in. :-(
The saga on MY recently purchased TW was that it was titled in Pennsylvania and was given as a "gift" to my co-worker by his dad (who no longer wanted to ride it). When my co-worker went to transfer it into his name before selling it to me, since it had "gift" under the purchase price, he had to get an affadavit of gift signed by both he and his father and notarized for both signatures. And his dad is still in Pennsylvania, while he lives in SF. Fun logistics for that transaction! All said and done though, I now have a clear title and registration.

$1000 for a CLEAN 2300 mile 1994 TW was worth the wait for me.
Good luck and I hope you get to enjoy that TW on the street sometime soon!
D