So I got the electric panel mounted finally. Sorry for the poor quality pics. I was in a hurry. Here are the mounting brackets fastened to the matching brackets mounted to the back of the cab, behind the carpeting. You can see the Swiss cheesing I had to do to the left bracket to make it clear the relay mounting bolts.
Here is the panel finally mounted. It’s quite sturdy and trucks in nicely against the back wall.
Now to get the battery cables ran and start wiring.