I'm wondering if there's something I can TEMPORARILY paint the stones
with to make a yellow brick road, something that won't wash off the first
time the sprinklers come on that same day, but something that will wash
off over time (even if it takes some scrubbing), yet also something that
won't hurt the grass.

Why temporary? Just paint the stones and when you get tired of it turn
the stones upside down

--
Free men own guns - www.geocities/CapitolHill/5357/