I get most of the stuff in that list done way earlier, at least 3-4 months earlier.

Packing usually isn't much of an issue since a lot of my touring gear also serves as my camping/emergency/earthquake/misc. natural disaster kit, so it's pretty much always good to go. Just gotta transfer from my backpack to panniers and head out.

If I run a new bike (almost never, but I got a new bike this year) I'll load it much heavier than what it'd be on tour and give it a good shakedown within a week or so after I get it. Any problems that show up get taken care of immediately. This time around I just had to get a wheel set that's a little more heavy duty than what came with my road bike.

I also make a pretty detailed itinerary printout, with target times, locations, possible routes etc. and leave a copy with someone in the off chance that something really stupid happens.