They may be T-1 Jayhawk trainers.
The normal colour scheme for them is predominantly white.
They are used to train both pilots and navigators.
If so I would guess they are most likely carrying out a low-level navigation exercise.
This cap looks to me to be more of a regular training flight flying circuits & landings out of Stafford regional airport.
The underground railroad preserved by BC is not a physical railroad with trains and rolling stock.
It was a network of safe houses & secret routes along which slaves could pass through the Union controlled northern states.
It is comparable to the WW2 escape lines through occupied Europe the escaping POWs used to get back to allied lines.
IMHO it would not be practical to transport dead bodies in this fashion from safe house to safe house.
However it would be practical to use it for people trafficking.
https://en.wikipedia.org/wiki/Underground_Railroad
Sounds like C-130 Hercules concur with >>3813603 but might be more general troop deployment related.
I'm UK based so not too familiar with US geography/military bases.
Is there an army or national guard base nearby?
If so it might be because units are rotating in/out to or from deployment/exercises.