CarolKay, do you need that ugly middle vertical latch piece to show in order to indicate items are on a trunk? Would the latch, rivets and some of the trunk be enough for the viewer to know?
If so, could you cheat and add something to Grandma's items by adding something counter in weight to heavy bottles, accordian etc? The photograph, simply because it's people, will garner attention.
I took your image, qwerck's image, and made another with Photoshop threshold. Perhaps think about light & dark shapes to tie the piece together and go from there?
I really like this piece; brings to mind the treasures in Mom's attic. When finished it will keep the eye & mind happy with all the things to look at, and stir emotions and remembrances as well.