Truck cover for long-term outdoor storage?

This is what I use, their quality is excellent:

https://www.carbag.com/carjacket/

 

that carbag site says "indoor use only".

 

I’ve used a few different covercraft covers and would suggest you check out their weathershield hd.
Please note, the stitching will mar your paint finish if it’s regularly exposed to wind.
Would advise against the Noah version as there is a coating that degrades after a couple years and leaves a persistent dusting of plastic residue (my guess) everywhere

 

I suggest placing arched spars across the bed, or a hard bed cover or a soft cover with spars, if rain or leaf litter might accumulate.

 

How about one of those tent garages?

 

Sell the trunk and when you need a truck a again, buy a used one. Letting it sit outdoors for a year or two there is no telling what critters will get into.

 

That's funny; when I bought my first one it said outdoor too. Meanwhile the owner/inventor passed the business on (I think to his daughter), so maybe they don't want to go out on a limb