I have a bit of a different take on this, learned from tripping in BJ74's for the past 15 years...
Being space constrained I have a 2 step process
1. Find boxes you like, that fit inside your truck. Other people have been sharing great ideas on boxes. I like the
Wolf Pack Boxes. They nest for easy stacking and tie, down. They are small enough that you cannot pack them so full that you can't lift them, and offer mutiple options to arrange them in your truck, and other than the latches, they seem to be pretty durable.
2. then 'Think inside the box'. What I mean is, don't take what you might need.... take only what fit's in the box! Dedicate a box for kitchen, for food, for tools, for spares, for clothes, etc. Then, being space constrained by a box, you are forced to carefully consider what you REALLY need to bring. You start thinking of things like how a loaf of bread takes up a lot of space compared to a box of granola bars, or a bag of peanuts will last all night around the campfire and take up way less space than a bag of chips. You also consider - What can I bring that has more than one purpose?, and - did I really use that thing last time?, or - am I travelling with someone who has that tool or spare part, so I don't need to bring a duplicate, etc.
Example... in my 60 series, with vast expanses of space, I have an axe, a hatchet, and a hammer. In my BJ74, I will take my
Estwing Fireside Friend hatchet, because I can make that one tool do all three.
"Thinking inside the Box" has really made me a more efficient packer, but has never left me without something I needed on a trip.