About how many acres did the Adams property cover during its most prosperous years?

40 acres in total, but the park in Quincy was set on 13 acres

Explanation:

John Adams was a second president of the United States, and also a very good in law, and he had in his possession one big property of 40 acres, in the state of Massachusetts, the property known under the name of Peacefield. He was born in Massachusetts, where he also inherited his big property. Those 40 acres belonged to his great grandfather, who moved to England.