SOLVED. Group of foster kids lives in cabin with aunt. [s]

[Lyndsay]

This book featured a teenage boy, a teenage girl, and her younger sister (who does not speak and wets her pants a lot). They are assigned to live with a woman (their aunt, I think), who does not show up, and they decide to be their own family in a cabin.
Someone sends them money for stuff, I think it's the foster stipend. The boy manages it.
At one point the mentally disabled aunt does show up, and they get snowed in. The girl is trying to cut wood and cuts her ankle with the axe. The doctors ask questions about their parents.

I think the title had something to do with "road". Or "Lane". Either "Down the Lane ____" or "The Road to ____" Or something like that.

[Valerie]

Long shot, but maybe Back Roads?

[Lyndsay]

It was "When the Road Ends"

[Kris]

Glad you found your book, Lyndsay. Thanks for the update. Here's the link - When the Road Ends by Jean Thesman (I think).