I don't think he'll ever fly in this plane. It will take 3 years probably to convert it to AF1 standards with all the inflight fueling, electronics gear and all that is required, plus pilot and crew training. It would probably be done about the end of his term. To fly privately it's probably $200,000/flight hour. He won't pay that. His old 757 I think sat in New York in disrepair for about 3 years, because he didn't want to pay to fix it. From what I remember it needed a new engine and some high$ maintenance. This gift is like a white elephant. He has a lot of money, but probably not 747 prince/king kind of money. Also at 80 years old, he probably doesn't have a lot of flying time left. Trump flying in a private 747 would be NFL player type stupidity. How fast can you go broke?
Now the idea of painting it in USA colors and parking it at a presidential library is interesting. That would probably create some interest in visiting. Regan has an old plane at his museum in Loma Linda and an old Beast limo.