I finally got my grandsons bed done. It turned out fantastic! I made it a bit shorter than your plans called for, the 4×4 posts are 4 ft tall, but I still used the 18″ drop for the rail and cleat. Since he's just 3, we wanted it a bit lower. It's the perfect height for us to stand and give him a kiss at the rail when he's in bed.
The hardware store I went to didn't have any 5/16 carriage bolts, and I didn't want to run around looking for them, so I used 3/8 carriage bolts instead. Also, instead of using a ladder, I bought stair runners (I think that's what they are called) and built stairs. I did put them upside down, that wasn't a mistake, his room is small and they took up too much room if we put them the right way. So I added another 4×4 post to attach the stairs to.
I used 3/8 hex screws (5 inches long) to attach the stairs to the posts (I predilled the holes to make it easier to put the hex screws in, but still took some muscle). I also added the decorative balls on top to 'fancy' it up a bit. It has 2 coats of 'natural cherry' stain on it.
Zayden absolutely LOVES his new bed and 'man cave'. The letters are just the inexpensive wood ones that I painted and attached with a smidge of poster putty. I'm going to add a spring tension rod and curtains between the posts so he can have a tent, without me having to clamp a blanket up there.
Thank you so much for posting your plans, they made this bed so easy to build….except for drilling thru the posts and bottom rail, that took some muscle. *lol*