Morning edwardo, I too did pr recently and found it to be a great lesson.
Personally speaking I started doing exercise daily, but as you say life can get in the way. I do 4 times a week now of an exercise program that suits me. But I have to say I do try to add a little something e.g. park further away from shop, take a short walk up the path or even while doing breakfast, stationary walk while waiting for toast to do, ( I can manage about 250 steps while waiting) every day. As for exercise after food, my preference is exercise first, build up an appetite, then have my meal.
If I fancy popping out, or having a tidy up and wipe round the flat, I class this as exercise too and sometimes it replaces the ex program.
Really I think we all do things that suit us personally, so if your doing something and it feels right, go with it.