We have a floor plan of the trailer on the computer. Everything that is in it is listed in the area of the trailer it goes with the weights of each item. (we had problems with sway on the former Tent trailer. All the storage was on one side)
We have numerous floorplans depending on the type of camping...weekend, week, travel etc. and time of year and if we are taking extra kids. We also usually don't camp at hydro sites so have all hydro related things in a bin we can take if we know we'ell have hydro. Of course when travelling the hydro stuff always goes with us.
We too have really cut back on what we take especially when travelling. If we don't use it on one trip it doesn't go the next.
We added a storage box above the propane
tank to keep outside related things in. Like the BBQ, Coleman stove, ropes, pegs, axe, etc.
The more you camp the more you discover what is convenient and what is needed.