With respect to your first point I would advise to give yourself some slack. Not only does the body need some rest days, but it will also help with willpower. My usual goal is no less than three days and no more than six.
Another thing that I tried and really enjoyed is the following: I started getting up from my desk once every hour, grab a pair of 7.5 pound dumbbells and do some mini sets of exercise, for example 20 squats, 20 overhead press, and 20 good-mornings. It takes like a minute, but it gets the heart pumping blood to my brain, and most importantly counteracts the "sitting is the new smoking". Give it a try for a day, I believe you might like it.