The best reasonable arrangement I've found so far, is to liberally lube it with a good oil and put it in a silicone sock.
A mix of good old STP and gun oil seems to be about right.
Then put that inside a hard case that's waterproof and air tight.
Something with seals.
I once did that with a shotgun, forgot about it for eight years, in a semi heated and cooled basement.
It was fine with only one spot of surface rust, under the fore-end, that didn't get lubed.
Lock the doors, they're coming in the windows.