Caster is not adjustable and has nothing to do with tire wear.
Chamber is not adjustable unless you buy adjustable plates.
Toe In and out does affect the inner and outer wear of tires.
I suspect in your case is that your springs in the rear are sagging... causing inner tire wear. And because of the rear spring sagging, the front is 'lifted' up causing your outer tire wear. So by replacing your springs, it should solve that problem. If you got 100+K miles, it is time for new springs... not sure about your shocks at this point.