The simplest theory is probably the best here. Hoffa was killed somewhere in the Detroit area after being kidnapped from the parking lot of the Machus Red Fox restaurant in Bloomfield Township. He’s not under the end zone at Giant’s Stadium. He’s not buried off the coast of Bermuda, Bahamas, or any other Atlantic location. There’s no way anyone would transport his body that distance just to dispose of it. He’s probably not in the foundations of the GM building either.
Most likely, they took his body up north (where I’m from and where - especially in the ‘70s - the region was sparsely populated and the roads were empty) and buried it on a farm somewhere. At it’s most creative, he could have been loaded on a boat near Detroit, taken out into Lake St. Clair or Lake Huron and dumped.
I doubt reality is as complicated as folks would fantasize it would be.
Mob hits are not complicated or driven by passion. Double tap, little ride in a trunk and you're removed from the face of the earth. Most murder victims are killed by someone they know, some sources say as high as 80%. The passions or complications of their relationships usually lead to the suspect.