Sovereign export/sale

[airstream50]

Hi, I am new in this forum. I am Italian citizen, and I live in Italy. In 2002 I married in Florida USA, and I and my wife bought a 1979 31 feet Sovereign Airstream. We never went on the road with it (except to move it for a few miles, after replacing breaks) because the idea was to use it as a stationary project.
Sadly my wife passed away in 2004, and since then I parked it in a private spot, and I pay a monthly fee for it. I had in these years the opposite feelings of selling it or import it to Italy, even if I don’t have a real project for it, but just because of affection. I will keep it in Italy too in a private area for caravans. Now some problems:
1) My mother in love has the original title, but she lost (or may be she can eventually find) the original bill of sale just a piece of paper sent to my wife (her daughter) at that time from the owner, but I believe it would be hard to find the owner again, he moved away.
2) The trailer has a Florida expired plate on it. I never registered the trailer at my name.
3) Moving it to a Florida port to export, and also on the road for some hundreds of miles, do I need a new registration? Since I never did it, and I don’t have at this time the bill of sale, could my mother in love sign on the title and become owner? She could sell it to me, with some sort of legal declaration. I understand I am may be breaking the rules, but I don’t know how eventually solve this problem.
4) If I want to sell it in USA, will the original title with the old owner name on it (there is no price sold on it) be sufficient? The new owner could just sign his name and go to register?
Please help, I eventually have a friend who can help moving the trailer to a port, but I don’t want to find myself and others in a big legal problem (and big fines) for it. Thank you for all your help