This is probably the wrong thread to address this but here goes.
First of all, this trust scenario seems IMNSHO way off base. There was nothing complicated about any of DM's real estate transactions and the fact that his mother is now running things indicates, there is no complicated behind-the-curtains trust operation with unknown people pulling the strings.
Secondly, I do not think DM is dense or a simpleton. I just don't think he's smart or highly intelligent, as his lawyer has maintained. He seems average IQ with a major ego to me.
As for leaving the evidence pointing at himself, as has been said many times before on this board, when he moved the trailer to his mother's, he was not a suspect. And presumably he was moving it from somewhere that people might be suspicious and could tie it to him -- ie the hangar -- to his mother's where no one had any idea about a chop shop, incinerator and all DM's other bad habits.
A trailer sitting at the chop shop hangar was far more likely to have people poking around inside it than a trailer parked outside Mom's house where the neighbours were not about to break it open looking for some new Harleys.
Finally, the body on the farm. If you believe as I do that DM killed Laura and disposed of her in the incinerator, he wouldn't be too worried about remains/evidence on the farm either. The whole point of buying the incinerator was IMO because DM believed it successfully got rid of evidence.
And yeah, I do believe that DM was dumb in a lot of his actions, which doesn't make him as a person dumb, it just makes him like a lot of other criminals, who don't realize everything they're leaving behind.
Addendum: I see others made some of the same points I did while I was busy writing.