Jim, I would definitely replace the thermostat unless it was replaced recently. Whether or not to replace the upper and lower radiator hoses depends on their condition, same for the accessory belt tensioner. You may want to replace the accessory belt while you have it off, again depends on the condition. If you notice fine cracks it's time for a new belt. Better to replace the accessory belt too soon than have it fail while you're driving.

__________________
Fred Hoelzle