US Airways Dividend Miles - From JFK to LGA for US shuttle to PHL: how much time?

I'm flying FRA-JFK in J on LH, scheduled to arrive at 12:50PM on 7/12. I have checked bags and would like to hop a taxi to LGA and catch the first available LGA-PHL flight. (There are flights at 2:59P, 4:00P, and 5:00P). Any chance I can make that 2:59 flight?

To complicate matters a bit, this LGA-PHL flight is the last leg of a *A award and I have the 5:00P flight booked. I know that *A awards are not allowed to be changed after the trip has commenced, but would US be willing to put me on an earlier flight nonetheless in this case?

I'm flying FRA-JFK in J on LH, scheduled to arrive at 12:50PM on 7/12. I have checked bags and would like to hop a taxi to LGA and catch the first available LGA-PHL flight. (There are flights at 2:59P, 4:00P, and 5:00P). Any chance I can make that 2:59 flight?

I'd say it's entirely possible, your main variables, assuming an on time arrival into JFK, are immigration and traffic through Queens, especially on the Van Wyck. The 4pm is a lot more likely though.

To complicate matters a bit, this LGA-PHL flight is the last leg of a *A award and I have the 5:00P flight booked. I know that *A awards are not allowed to be changed after the trip has commenced, but would US be willing to put me on an earlier flight nonetheless in this case?

As a US Gold you can move up as usual at the airport assuming there's space.

Your thread title mentioning DCA rather than LGA I'll admit confused me :-)

If you're checking bags at LGA, I bet you end up on the 4 PM.