Where you wind up will depend on how much you can afford/how many bedrooms you need/how close to the beach you want to be.
I am the rental manager of our Spring Lake office and would be happy to help you. Just email me via Trulia or my website below. You can also search for rentals there and find information about some of the local towns, too.
The areas you mention are at least 2 hours apart so you can try to locate somewhere in the middle but you are looking at at least 1.5 hour commute What I would suggest is to live closer to one destination with easy highway or train access to the other destination. This would depend on whether you will be mostly working in NYC or Philly.
If you want to be closer to NYC I suggest sea bright or Monmouth beach because you can find affordable rents and have east access to NYC. There is also Atlantic highlands
If you want to be closer to Philly then you want to be south in places like sea isle. Barnegate stone harbor etc
I suggest you look at a map to start your research then decide which areas are geographically acceptable to narrow down your search. From that point you can zero in on some towns and viable options