I learned to hate my back pack... PITA to use... not enough protection while in transit. What has worked was a shoulder bag AND the pelican. Everything protected/secured in the Pelican with cable and padlock. I would pack just the stuff I wanted for the day in the shoulder bag. The Pelican would then be locked and cabled to something solid the in hotel room out of sight.
I also hated the pluck foam stuff.. messy... not efficient in space use.. not reconfigurable. The velcro divider sets solved all those problems.
This is just one way to pack a relatively small Pelican 1510 with a lot of stuff....