Stewing cooks the meat long and slowly, ideal for breaking down tougher cuts. For any animal, pick the cuts which have done the most work during the animals life. For example, shoulder of lamb works well as it's constantly helping move the animal around and support the head going up and down scoffing loads of delicious grass. For cows the tail is a good one after a life time swatting flies all day every day.
The quantity of fat in shoulder also helps as this will leach out into your stewing liqour, fat in the liqour will help it store more of your stew flavours (I'm told some flavours will bind to fats ut not water) and help those flavours from your stew linger on the tongue longer.
So, pick some hard working cut ideally with some fat (although bacon/belly pork is always a good substitute), depending on the life your goat's had this could certainly be shoulder and or neck and quite likely the legs with maybe some help from another source of fat. If you're using neck or any cut with bone in (ie neck) I'd suggest leaving the bone in during the cooking to improve the flavour of the stew, people can always resort to fingers if need be to get at the meat.