I had your same luck when I was volunteered by the family to sell my grandmothers car. She had driven it very little in the year before we took her keys away. It was a 20 year old car with 29,000 miles of mostly sitting.
I drove it from her place over to my house and I heard a funny noise just a few block from home. The water pump just let go.
It was a early 1970s Impala so it was not a major task to change the water pump. The bottom hose was about to blow so I had to replace that and all of the fan belts were just cracked and crumbly so those were replaced. The oil had not been changed a long time so that got changed.
The radiator had a decent leak once the new water pump could pressurize the system so I had to pull the radiator and have it re-cored.
It needed new tires as well but I was not going there. I did have to change the read brake cylinders on the drum brakes as well.
In the end a running car sold for more money. I still spent an entire weekend working on it. Granny gave me a hug which totally paid for the work. I wish I could get another hug from her.