I have had rifles that looked just like yours and it is sometimes amazing what some TLC can do.
I would take the stock off, then virtually soak the metal in kerosene. Strip off a piece of metal foil, longer thatn the barrel and action, shape it, put the metal in it, then kerosene, turning it over once in a while.
Some of the rust might come off and what rust is left will come off easier. Like they said, use oil with steel wool, as fine as you can get and go real easy,so as not to take off the bluing.
Go very easy on cleaning the barrel. 22 barrels are damaged more by cleaning than by shooting.
Winchester 67 rifles sell at gun shows for about double of what a similar Cooey would sell for.