Pacific Northwest lurker here, finally stepping into the light. I just got a Big Joe after a few years of wringing my hands over the investment, but I couldn't be happier now that it's here - more importantly, the better half feels the same way. I'm looking forward to learning more, and at some point giving back to the folks that have contributed to teaching me so much about one of my favorite ways to cook.
To start, for any newbie like me that had spent lots of time trying to figure out where the kamado was going to go, I'd like to add to the recommendations on the tried-and-true Grill Dome design for a table (XL). I used pressure treated wood, both new and salvaged, for all but the top and some trim pieces, where I used cedar instead. I also added a 4x4 cross piece at the bottom of the table legs at each end, to provide side grain attachment for the stainless 4" casters I used - that idea came from work bench plans I found while shopping for casters. I spend close to $350 when all was said and done, but most of that was due to my preference for stainless parts, being that I live in coastal Oregon, so rain and salt-air are constantly working at destroying all things that oxidize easily. I followed all dimensions on the GD design, with the exception of the 2x6 support-shelf planks, which I felt better about supporting the grill over time.
Fire bricks added the finishing touch prior to lowering the Joe into place, my preference over the provided 'feet', to provide more shielding between the wooden table and the bottom of the cooker. I used 'water-seal' on all horizontal surfaces.
For anyone wanting a cover, after building a GD-designed table, you might also consider the appropriately sized GD cover, as I found that the XL cover fits my KJ Big Joe / table just shy of perfectly.