Cool idea Alan i like the adjustable aspect. Quiet a few years ago i made a similar hauler but for manual hauling of drywall. My bed was fixed and i built an angled frame up 4ft high to rest the drywall on that i had to move from back of the house to my shop. I had to chuckle when i saw you going through the window to pass your wood to your shop. You lucky to have access this way. I got luckier back in my day of the same experience when i planned on building a canoe in the basement and with way houses are packed on top of each other where i was at the time, there was no way to get out the basement, SO missus who spotted the problem said well you just gonna have to build a shop outside for yourself. That was all i needed as motivation to do it. Sadly i aint on that property anylonger but your post took me back to the cart i built which i still have for hauling long stuff. I like your improvments though.