Why is your focus on trialing the run?
I watch for players following the play who may still be trying to catch the runner, or may be giving up on the play. This is where blocks in the back and unnecessary hits usually happen. Once the play is over, look for cheap hits around the pile. I think having a wider field of vision helps you in these cases. Don't work too hard to stay up with the runner. Let them go by, then keep an eye on the pack trailing the play. Also, as the umpire I generally watch the middle of the field into the play if it's in the side zone. Wings and BJ have everything else covered. If I move down field the R is still behind me cleaning up.
In 5-man, if the play is in the side zone, the wing, U. R and BJ should have the end of the play traingulated. The opposite wing has back side.
