Can entering a 1099-R be simplified to avoid a difficult to answer distribution source question for thousands TSP Hawaii tax payers receiving RMD from the TSP?

It depends on how your TSP plan is structured.  If it is a Roth TSP, you would answer none of the above. A Roth TSP is one where you actually contribute to the plan with after tax dollars so this means that you invested in the plan.

If it is a regular Tax-Deferred TSP, then you would answer that question  "Government, military or other qualified pension where employees don’t contribute"