You could do a lot of work but first clean out that breather and air cleaner box. Then drive it for a few days. If oil saturates air cleaner box again in say two days. It possibly is a pretty worn engine unfortunatly. Does happen through neglect or high milage on most engines eventually. Use of a higher viscosity oil in spring/summer and fall does help somewhat to lessen consumption. Thinking a straight 40-50 rather than a multigrade. Would be nice if just leaking for the majority of your loss instead .