OK I spent several hours clearing out the monsters and rails, barrels, and doing the run backwards and forwards and can get the trophy but with not even enough time to get back to the start.
I do not normally use a cheat but is there any way the Rustlers run Trophy
can be added to your inventory? IO tried the jump2 cheat and it did not work but perhaps if I get off the horse it might. There does not seem to be a cheat to complete a particular quest so any help would be great

an even dumber old guy
Tarnacc