That comes to approx 20cpm for the 2643PQM you need (the extra PQM is worthless). I've also been offered smaller amounts of miles at check-in, but they typically are are 20cpm, so even if the offer is 3000PQM, still comes out about the same price.
If you decide to fly, LGA is easier to find because it typically requires a connection somewhere. Example:
UA:$148 LGA-FLL 3830PQM
Tue 13 Dec
UA463 LGA-ORD 0800-0937
UA1810 ORD-FLL 1040-1449
UA2040 FLL-ORD 1545-1808
UA1023 ORD-LGA 1915-2229
https://goo.gl/flights/CRiZ
If you don't drive to the airport, then it's also possible to depart LGA and arrive EWR (or vice versa).
Good luck!