Saw this on Flyertalk and thought it worth sharing:
Anyone needing a mileage run on United from Philadelphia or New York:
On December 10, 11 and 17th you can travel on United from Philadelphia 30th Street Train Station (ZFV) to Las Vegas for $121 round trip. You can do a same-day turn, returning on the red-eye nonstop to Newark. Nets around 4,800 EQM if you travel via Houston on the outbound and about 4,400 if you fly nonstop from Newark.
– Here’s the deal with the ZFV-EWR leg of the trip. You SHOULD NOT skip that leg if it is at the start of your trip. In other words, if you are traveling ZFV-EWR-LAS, you SHOULD NOT skip ZFV-EWR. They may cancel out the rest of your reservation. If you are traveling LAS-EWR-ZFV, the general consensus is that you are fine skipping EWR-ZFV. These are one way fares, so to be safe you may want to book each leg separately.
– Amtrak legs earn 250 miles, but they DO NOT count toward Elite status (ie, they are NOT EQM).
– If the return flight LAS-EWR is canceled, they MAY put you on a LAS-(ORD/IAH)-PHL flight since United thinks you are going to Philadelphia. Pretty outside chance, but it’s possible.