Join Date: Oct 2010
Location: Scandia, MN (just north of St. Paul metro area)
You didn't mention what material would be used for the project. Hardwood, or regular lumber-yard construction lumber? I'd recommend moving the tenons to the center of the uprights, a 1/2" X 1/2" remaining corner material doesn't have much strength. I'd go with total of four bedbolts per corner, and do the same on the lower connecting rails as well. And make sure that the rails seat on the shoulders of the tenon rather than on the end. I wouldn't trust pocket screws for this application.
What is the overall height of the bed? Without diagonal bracing, and with no lower connecting rail on the front side, I doubt that you're going to have much stability. And on the front, because of the step-through for access from the ladder, there's only 1 connecting rail between the two end posts, putting considerable strain on the one joint. Two youngsters rough-housing on the bed are going to put stress on all the joints.