The seat will bolt right in without any problems. Just installing the newer dash will be a killer. The hole dash on the newer model truck will completely unbolt from the firewall. cutting and forming the newer model dash will be your trouble side. even though it don't look it the newer model dash is anout 4" wider then your 79. I'm sure it can be done, But your fab skills will have to be good and don't plan on it to be a weekend bolt in job.
I remember seeing some company that sold a kit to do it, but I forget where I saw it at. I remember that there were pictures of them taking the dash out of a 93-96 Ford Truck/Bronco and putting it in a 1978 Bronco.
Aside from the seats, anything related to the interior will require mild, to extensive, modifications... IIRC, the 92-6 dash is narrower(not by much tho), and the door panels are longer
I had wanted to do that too, til I found this little bit out, and decided against it