You should beware criminals from Philly seem out to the surrounding areas. Sheriffs and police generally know the laws regarding open carry, especially after last year's MPOETC training required by all police.
If you're worried about MWAG calls, you should call the area in which you're traveling before hand to make sure officers/dispatch knows to ask people if the person is acting unlawfully.
If you're confronted with a 'I'm going to run your gun' attitude, stay quiet and mention case law, depending on the situation mention a lawsuit.
Police in the area should be kind, courteous, and professional.
Just out of curiosity, which area are you visiting specifically?