Same layout for the bottom frame with the exception of the 2x4 inserts running the length of the bottom which will be used to attach casters to. the reason for hte colour difference in the pic is because they are pressure treated lumber..for no reason other than I happen to have a p.t 2x10 that I ripped down size to use.
The only hiccup was when I realized that it would be in the way of the cross members. I didn't want to put the "caster rails" (for lack of better description) on the bottom of the fram as it would then add an extra 1-1/2 to my plans so I ended up running the caster rails from inside face to inside face of the end pieces and notched the middle crossmembers with a jigsaw to straddle them.
The only hiccup was when I realized that it would be in the way of the cross members. I didn't want to put the "caster rails" (for lack of better description) on the bottom of the fram as it would then add an extra 1-1/2 to my plans so I ended up running the caster rails from inside face to inside face of the end pieces and notched the middle crossmembers with a jigsaw to straddle them.