We use Essington Ave too. Going North on 95 it is the Bartram/ Essington exit--14 I think.
We have used Sunpark recently (in Sept. and Dec. ), they have AAA rates as well. We plan on using them again next week. Do a search for Sunpark--they have a website. We learned about them in the Inquirer last year when they ran an article on parking options.
In the past we had no problems with their shuttle- wedropped off the keys, loaded our stuff in the van and away we went. For pickups, we called on our cell, but both times another driver happened by within minutes and we waved him down.