New car!! Need advice on starting!

I have found an original 49,000 mile 66 dart GT.
The car was driven twice a week till last year when unfortunately the original owner of the car died. His grandson (in his 40's) drove the car to the family farm and parked it next to the barn. This is where I found it.
I bought it, put some air in the tires and trailered it home.

The car cranks over easily enough but I havn't tried to start it.

It has the 225 slant (with "charger" on the breather)
I would assume I would need to change the oil and get new plugs but what can I do about the year old gas in the tank and lines?
How would you approach this?