Hello Brains Trust
I've recently started doing some renos in our house and have learnt so much along the way. I am hoping to build a little loft play area within the playroom one day (after finishing other simpler projects) and I've tried looking everywhere else for my queries but seem to have hit a wall.
What type of timber should I be using for structures like this loft bed? Do I need structural/MGP pine or is DAR timber sufficient? Can timber shorts be used? What about timber battens – are they structural?
For some reason, the only structural untreated MGP at Bunnings seem to be out of stock everywhere. Can anyone please direct me to somewhere I may be able to obtain suitable timber for my project?
Your expertise is much appreciated. Thanks.

Inspiration/picture source: https://www.ana-white.com/woodworking-projects/playhouse-loft-bed