I'm not an expert, but have had some experience with the Commonwealth of Pennsylvania in this area. The bottom line is, you need to go to a capable notary public that deals with titles and registration in your area. Most AAA offices are reasonably capable, if you're a member, although there are also many other private notaries available. The process will likely depend on whether you transferred the title and registration to your name at the time of purchase (and paid the sales tax). If so, getting a duplicate title will be a matter of filing the right form using the VIN and paying the fee. (That may even be able to be done online with a credit card.) If the title was signed over in NJ, but not yet transferred and registered to you in PA, the process may be arduous and might include running ads in the paper looking for the original owner, before proceeding through the "lost title" process. Some states require the title transfer be notarized at the time of sale. Pennsylvania is one of those states. Depending on whether NJ is a reciprocal state in this area with PA, could complicate things. PA may want the former owner present for the title transfer. (This is the situation I'm currently in for a small utility trailer; looking for the original owner (also a PA resident) to resign the title in front of a notary.) So, based on some limited experience, my opinion is to either find the title (which may still only be the starting point) or move to Maine.
Good luck and we hope a notary can help you through this,
Roy and Marie