I started looking for plans for a bunk bed for my grand kids and found Ana's Simple Bed and Simple Bunk Bed.
I took the advice of some of the posters here and used head board plans for both top and bottom beds. I drew up the entire bed in Sketchup prior to building and realized I could improve the strength a bit. The attached pictures illustrate those changes. I used laminated 2 x 4 posts for the legs and cut a notch to receive the rails into that notch on the inside 2 x 4. Making the rail longer to insert into this slot allows the bed to be supported directly on the 2 x 4 instead of relying only on screws. I then used 5 1/4 lag screws from the side through the 2 x 4 , the 2 x 6 rail and into the head board structure. Additionally, I screwed in triangular corner pieces under the rails to reduce racking when the kids play.
Making these changes, I also attached the end supports for the spring/mattress only to the head and foot boards which allows the rails to be separated for transport, i.e. smaller pieces. This thing is heavy!
I also slotted the stanchions on the guardrail for the top bunk, inserted into new supports, so it can be removed for easier changing of the sheets.
The kids really love this bed and played in it for most of the time they were visiting. Thanks Ana for the initilal plans.