Luggage suggestions for KZ550 LTD?

Got a 1982 KZ550 LTD and now that I live in town I've been using it for tons of stuff, since I know I can easily just run back and grab my car if the weather gets too bad or if I need to pick up something larger. But right now if I just want to run across town to check something, I have to carry a backpack if I want to even carry a hat. Plus, I can only do light grocery shopping (like, 3 items max) if I happen to have an empty backpack.

Been looking at some storage options that can A) Lock to the bike (so I don't have to carry them into every building) Lock the lid (again, so I can leave it alone), and C) Water proof (since I will ride if it's rainy for part of the day). Thing is, I definitely don't want my bike to start looking like a retired Hell's Angels cruiser or anything. I'm more the 22 year old dirt bike/sport bike type, not the Harley type. So I'm looking for something without studs and tassels and all that Something either simple or "old school" is cool (for instance, old WWII style bags, more utility and not stylish).

Saddlebags, tank bags, don't care what it is! Any suggestions?

Some of the ADV riders convert ammo boxes into panniers. You'd have to rig up your own mounting hardware and locks. But you're probably going to have to create your own mounting hardware anyway.

You could install a luggage rack & trunk.

Universal fit KG luggage rack.


Locking trunk - large. I don't think it's meant to carry much weight... 20lbs?
Unlock trunk, then press button & lift trunk to remove from bike.


Trunk base bolts to luggage rack.