F A M I L Y

 

Rumble, echo, steel rails- a trian of course.
hole in a mountain- a train tunnel
choir sings nearby- there's a church nearby
so close to home- "duh".
a baseball field- double "duh".

This gives her a fix on where the next clue is.

Thus, she is to go to the train tunnel by the baseball field and find the special rock. This was inspired by the film "Shawshank Redemption" (no, I didn't read the book). The rock was a plain rock, about 1" thick by 3" wide and 6-7" long. It had a BIG yellow Happy Sun on it. Beneath the rock was Heather's next clue: