Requirement 4 said that it had to be easily transportable. And so it is. The legs I got from IKEA come in 2 parts: the mounting plate and the leg itse...
Step 8: More sanding!
Okay, so you've cut out your pieces, and you've routed the edges, now what? Make all those cuts smooth. I have no doubt in my mind that all your cutting will have left you with some fairly rough wood. If you have some exceptionally rough spots, you can use some 60 grit, but I think for the most part you'll be fine with the 120. When you think you're done, wipe everything down with a soft cotton cloth, preferably a moistened microfiber cloth. The moister helps grab stuck sawdust and it will make any loose grains of wood stick out. Those need more sanding.
When you're done the second time around, whip it down again and hope the weather is fair.