249G: Treasure concealed in a barn

I read this book in the 90’s but do not know if it was published prior.

There is a young boy whom begrudgingly goes to a family members home (may be a grandparent although I do not recall this aspect specifically). I think it was for his summer vacation. There is a local legend of missing treasure, maybe it was stolen? Many people have looked for the treasure over the years, but of course the boy finds it in a barn. I think the barn was on the property where he had been staying for the summer.

The treasure had been melted down and molded/crafted into items commonly found in a barn and covered or painted to conceal it. I believe he chipped off some paint of a candle stick or something, and the wagon in the barn actually was made of gold and also painted or covered in disguise. I hope this is enough to figure this out, I really loved the book as a kid and now want to read it to my children.