Trading Spaces?

Scott's dad came up with an interesting proposal...

Their house & yard is too much house & yard for them. Our house is not enough house for us. So he proposed that we trade houses. We keep our same mortgage payments and same everything, just switch places we live. Interesting idea. Would solve our space problem without costing us anything.

Some concerns:

1) While we live on a busy street, they live on an EXTREMELY busy street. Scary.
2) They don't have heat or air conditioning at their house. I think that would need to be addressed. It gets so hot here in the summer. And it's also nice to have the heat to take the chill off on cool/rainy winter nights.
3) If we move any time in the near future, they'd have to move again (back to their house).

But definitely something to think about.