These dimensions might be a work in progress. I already made the drawings more detailed than what I used to build it...
I started out with 2pcs of 14ga 2" square tubing 132 inches long like this:
I cut V shapes out and left the outside wall of the tubing in tact. I then folded at the V cuts and welded.
I then welded to 35 inch long cross pieces to make the main part of the frame.
My casters were 7 1/4" tall so I made some plates to attach to the top of them and welded a 6 inch long piece of 2" square to them. The rear wheels are flush with the back of the main frame. I positioned the front ones by putting a straight edge on the 45° angled part of the frame and pushing the casters up to where they are touching.
For the parts that go up to the cab mounting positions I used 10" long pieces of 2" square tubing. The rear cab mounts are higher so I welded them to the back of the frame where they stick up 8 inches above the frame. The front ones are welded to the side of the frame and stick up 6 1/8"
This should get you close enough to duplicate. Let me know if you have questions.
I think the steel cost about $135 and I already had the casters.