you're in NJ............I would just contact your local "goombah", I'm sure they have plenty of experience on how to go about to title a car, that has no title
No big deal FrankSquid, I've done this before in NY, I would imagine it's the same thing on your side of the river.
When I got an old Maxima from a customer the title was missing, it's not that difficult to get.
Basically there are two things that need to be done. First get the paperwork from DMV (to replace a lost title), but don't fill it out yet. The requirement is that the last registered owner must fill it out, and the title will only be sent to them. If you don't know them you are still not completely screwed, but it won't be quick and it won't be easy. Your sister was the last owner, so no problem there.
1.) Have your sister fill out the papers and sign them.
2.) The second issue is getting a good clear pencil etching/pencil tracing of the VIN#, I sent two etchings to ensure that one would survive the mailing. This can be difficult to do on some cars, it may take a very short pencil and some patience, but you'll get it done.
They said it had to be the dash VIN, but I suspect the VIN on the door(if still there) would suffice, provided it's done using the same size stamped letters as the dash.
Make copies of everything (for your records) and mail to your State DMV office, probably located in Trenton, or to the office specified on the lost title request papers. Speaking with a supervisor at a different office could clear things up if you have questions, many workers don't know what they are talking about. When I wanted to register my truck in NY usng my PA drivers liscence they told me it couldn't be done, but I had a customer who did it with a FLA liscence so I knew it was possible. After SEVERAL calls I finally got someone on the phone that knew what to do and told me what documents were needed.
Also I know a few used car dealers who practically live at DMV and know the system very well, I can ask them if you like.