I'm sure you can walk on your roof without an issue. But like you said, you can be cautious and use a piece of plywood to distribute your weight. You should be ok though.
2013 Jayco Eagle 328 RLTS
2013 Ford F350 6.7L 4x4 CCLB W/Air Lift air bags
2002 Coleman Bayside Elite (traded)
Me, Momma and Charles (RIP buddy)
And introducing Sofie!! ;)