Hey Ken
I use both pocket hole joinery and dadoes as each have benefits and liabilities. For your router table i'd opt for dadoes. A router table doesn't need to support much weight but it does have the racking / twisting forces associated with routing operations and the dadoes will be stronger in that regard. With a little advanced planning you can also use the dado setup for making your face frame pieces at the same time.
I'm assuming your using 3/4" material so all your dadoes will be 3/4 by 3/8 which makes calculating material a snap. Once the dado width is set it's just a matter of moving the fence to the correct distance from the blade and cut away. I find this method much easier to deal with at assembly time since i don't have to worry about pieces shifting around when i drive the screws.
As to your design, may i suggest you move the bottom piece up several inches so you can add leveling feet or casters and keep them hidden from sight. It's also a good place for blocking to add some rigidity to the cabinet. Also, depending on your plans for the large cavity on the bottom, a center partition might add some flexibility with door/shelf/drawer designs down there.
Let us know what you decide and post some pics of the progress!
Brian
