What would you recommend for treatment for a missed cuboid stress fracture (caused by walking for exercise)? would crutches help 4 months later?

See podiatrist/ortho: What your next step should be depends on how you feel now, & how severe the fracture is. See an orthopedist that deals with foot & ankle problems or a podiatrist that does. I see that you're on warfarin, heparin & taking tylenol (acetaminophen). It is NOT a good idea to take Tylenol (acetaminophen) with those meds. If you have been doing so, call MD, it can increase the effect of those meds, and cause too much blood thinning.

Not too Common.: I guess this means that you are still having pain the cuboid area. I am not exactly sure how you have come to the conclusion of a missed stress fracture, but if that is true, then crutches are a good option. The foot should be in an immobilization device such as a cam boot. The boot, with crutch assistance should be enough to start. These fractures can take 6 months, some a year. See a specialist.