Starting the floor
I made a black paper template of the floor, then did some math and determined 5.5" x .75" boards would work best, so I drew lines on the paper to test out the placement. This is the same material used for the siding but left full width.
I used the same painting technique as I had for the siding for the base color. I applied a few dark washes to age the planks, even dropping some puddles in places to make stains. These were lifted and reapplied a few times over.
I spread the glaze in my paint pan and pressed a paint bottle into it. I pressed the bottle randomly in the corner of the floor, and it left some nice detailing there, where a bucket or paint can had once leaked. I lifted the paint a little to make it less fresh.
The Datsun kit comes with 5 tires, so I took one and rolled it in black paint. I pressed it onto the floor to leave a tread impression. I lifted that as well and then spread a grey wash over the whole floor to tone down the stains. Then I added a few small newer ones. It's easy to add more mess, but it's hard to remove if you add too much.
It's now back under magazines pressed to dry. We'll see how it turns out!