Just finished making an inexpensive storage box for the pass-thru in our 228 Jayco. Works good for storing tarp poles, axe, wiener sticks, fire poker, etc.
Total cost about $14.00. Materials needed; four 1" x 6" x 6' fence boards, #6 x 1" screws and an about 1 hour. Totes still fit, actually makes them fit tighter and will keep them from sliding around during travel. Easy access from either door.
My carpentry skills leave a little to desire but it is just a storage box so it doesn't need to be pretty.