What do I do while not doing formal walking or sitting meditation?
If it is at all possible, just continue like you do during walking meditation; Radiate Loving-kindness to all beings you encounter. Whenever you get distracted, you apply the 6R’s.
If you are doing extremely complicated stuff, you might still be able to radiate, though maybe not as strongly.
If you can’t practice, just Smile all the time. A little smile on the lips, and smile from the heart.