"The wife is complaining! Any suggestions would be greatly appreciated. Thanks! " So it boils down to keeping the tractor or keeping the wife, I see....
The warming up part and something in the safety circuit don't seem to mix. Does it seem as though there is too much of a load initially, that the engine is "cold blooded' or that a switch simply shuts the tractor down to you- given the choice to pick one.

To add to tomplum's probing, let me ask: Is this a manual transaxle or a hydrostatic drive tractor?
If it is a manual transaxle, will the engine die the same way if you let out on the clutch/brake when the trans gear selector is in neutral?

If I had to pick one, it would be the engine is cold blooded. Also, this is a hydrostatic drive tractor.

If your Kohler is carburated look to the the idle and slow speed circuit in the carb for blockage. Also the anti-backfire solenoid in the float bowl.

Look for an air leak between the carb and manifold and between the manifold and both heads.

Check the choke mechanism for proper operation.

Take a look at the air filter... both the pleated pleated and the foam pre-filter.

By any chance, did this problem surface after changing a fuel filter?

Is it maybe a matter of fuel getting older, weather getting colder? There is also an updated carb for the CV twin on Prestige tractor in this years service school notes. There is also a separate service bulletin I believe. I would think your local Simplicity dealer is familiar with it.

Do you think the updated carb could be the fix for this problem?

pull your choke full out to start the engine. as soon as engine catches, push choke back in part way so that engine runs reasonably well at mid-throttle. should then be able to let clutch out without engine stalling. Gradually over the next cuppla minutes, push choke all the way in (off).
doing this is helpful in starting a cold engine, particularly as ambient temps are falling now.

@rcbe: I tried your method of starting the tractor, along with cleaning the contacts of the safety switches. SUCCESS!!

THANKS TO EVERYONE WHO CONTRIBUTED!!!!

Cool. Thanks for posting and replying.