Very good write up! I have been working on my new sump design in Sketchup.
The biggest trick to Sketchup is to re-map the hotkeys, so you can select between your common tools with one hand, while keeping the other on the mouse!
It's also very nice because you're actually drawing plans to scale. I just plain at drawing ideas on paper.. to scale.
Tip: With the tape measure you can use it to measure distances, or draw in measure guides. Select your tape measure, then press CTRL, and you will notice a + appear and disappear beside your tape measure.