One thing that I found that helps when making insulated doors is to fit the frame into the door opening, wiggle it back and forth until its square to the opening and then put a cross brace on it.
My door opening wasn't exactly square and the door wasn't either. I left the brace on until I had the exterior skin glued and stapled on. Then it kept its shape.
I used the same t- molding that Mike did but I used a regular aluminum piano hinge instead of Grant's hinge. If you do it this way, make sure and put 1/8"x1" aluminum strap under the body side of the hinge to shim it out a little. Otherwise there isn't any room for the weatherstripping under the trim when you close the door.
My door is a little over 2" thick and the door is 1/2" smaller around than the door opening. I found out the hard way on the teardrop that the door will seal better if you put the latch in the middle of the door.
Bruce