I only have a small oven so I'm not doing a whole turkey, I've made Delia's turkey roulades but there are some instructions here about cooking a turkey in parts, the limbs don't take as long so when they are out of the oven there should be room for the roasting veg.
You could do the turkey first then cover it in foil to keep hot while you do the tatties and veg. If you boil the ham, could you finish the glaze off in the oven while you are dishing up the veg? Or, take the veg out when they are done, cover with foil and put the glazed ham in to finish off then.
If you have a separate grill you could put the veg tins in there to keep warm.