Started putting it together.

Started with the main frame.  Since I've never done this before and it was for my grandson, I used Titebond Ultimate and then used construction screws for good measure.  I don't think I needed the screws cause the glued up parts were really solid.  If I make any more of these, I'll just clamp and glue.  This was going to take a while to make just a single unit, but if the parts were all cut and available, with knowing what fit where I may make a few more to try and sell.  I won't put Caterpillar out of business, that's for sure.