Also consider shelters generally banned weapons and are dens of communicable disease and bed bugs (I'm horribly allergic to them so I'll never step inside a shelter).

When I was homeless I lived outside because if you have a decent tent and sleeping bag it's perfectly comfortable, and I like to have a weapon handy no matter what and I reject any living circumstance that would prohibit that. At no point did drugs enter the equation, but if they did, it wouldn't have changed the calculus.