One other thing to consider...
When I parked at EWR, it was always a hassle. Off-site or on "economy" on-site, it always took longer than I'd planned and I ended up stressing about my flight. If I priced out the cost of "better" lots, it started to get really expensive. Turns out I could get a town car for about the same cost as parking. So for the same money, I got a nice, stress free ride to the airport, and then had some guy waiting for me with his little sign waiting to pick me up.
Hopefully somebody else can point you to a good lot. But if possible, check out what a car service will run you.