In most cases Priority will be there in 2-3 days anywhere in the Continental US.
A lot depends on the volume of mail the Postal service is handling at the time, such as 1st. of the month for flyers and especially Christmas!
I once had a package take 12 days to get 2 states over during the Christmas rush.
Postal employees tell me to just imagine 2 boxes, one with 1st. Class, one with Priority. 1st. Class box gets loaded when it's full, even if it takes a few days.
Priority box gets loaded daily, no matter what.
It is all handled the same, such is the reason 1st. Class sometimes is as fast as Priority.
Only Express Mail gets full "Special" treatment, it goes VIA special carriers, IIRC.
Apply extremes to the above scenarios for Parcel Post & quadruply so for Media Mail (Media Mail should be outlawed, IMO)