Utilized the plans from this website to frame out the general idea, but as typical with my projects, I took it to a little further and utilized more traditional joinery (mortise & tenon, oak dowel pins, dado). Guard rails are bolted with carriage bolts. Hand planed all boards and added chamfers to every edge (zero sandpaper). Both beds are joined together with 1 inch oak pins (x4 legs). Each bed breaks down very easily by knocking out the three 1/2 pins that join the legs to the stretchers (x4 legs).
Both beds were built out of structural southern yellow pine lumber. The boy's bed was merely varnished with Danish Oil (dark walnut) all over - on Southern Yellow Pine, this color choice gives it a rustic look. Girl's bed was two toned: painted white and stained with Varathane (Kona), to give it that country look.
I think the total installed cost of the beds was just over $300 - $350 for the lumber, oak pins, any hardware, and finish material. This was a while back, so with lumber prices high, I'm not sure that's easily done anymore. But, it's solid as a rock and will last an extremely long time for our family.
Great project. Thanks for the ideas! Steve