Wow, there is a lot of advice on doing special things and adding special products to deal with 3 year full tank of gas. I was going to say.... Since the rig is running fine, just use the rig for all your local travels around town to your job and stores until the tank is 1/8 full. Then fill it and rest easy.
Now there are other non-gasoline matters to take care of like change the oil after your first run to the store, inspect for rodent damage, maybe get your brake system inspected for disk brake rust damage, flush the braking system, etc. etc. Such matters are dependent on whether the rig was stored in a garage or outdoors.