Wall attachment

How are folks going about attaching things to the trailer walls? Like hanging cabinets and such.
I'm going to be building a cable/pulley bed this weekend like the one in the video in the other thread. I'll have rails or 2x4s going up the walls and across, but how are they secured to the trailer walls? I'm contemplating drilling and tapping the studs with 1/4-20 bolts or something. It doesn't seem like sheet metal screws would do a good enough job.
Please help educate me.
I'm going to be building a cable/pulley bed this weekend like the one in the video in the other thread. I'll have rails or 2x4s going up the walls and across, but how are they secured to the trailer walls? I'm contemplating drilling and tapping the studs with 1/4-20 bolts or something. It doesn't seem like sheet metal screws would do a good enough job.
Please help educate me.