I really like using the ledger board on the 2 x 4 leg to hold the weight. Then the screws are only holding the board.
I had to cut level 1 on that layout into 3 sections. We have to diassemble and move it to it's final location in the museum. I only had to a one or two joists in the center of the ends from the original construction.
I did add a few more legs.
The framing and legs are fine for weight. It will jiggle a little due to no diagonals for the legs. May add a couple after it's in it's home.
Your layout will have a some weight than this one, so perhaps a tighter grid.
Like Dewey said, it's tough to get straight 2 x 4's today. You even have to go up a grade on the 1 by's to get straight pieces.
Many like "house like" structures when it's not really needed.
