Dear Peter,
We're so glad you're coming to join us on Sunday. Here is how you can find us. We'll have our picnic in the People's park. You know where that is, don't you? After you enter the park by the main gate, walk straight on till you come to a stream. Cross the stream and turn right. After walking for a while, you'll come to a hill. Walk round to the other side of the hill. There you'll see a lake. We'll have our picnic there in the small woods by the lake. I'm sure you'll have no trouble finding us. Do come.