Tales from Basically Everywhere

http://jowybean.deviantart.com/art/TAJ-Deal-with-it-516692954

A princess lacking any royal duties gets bored and abducts a farmer who's looking for more than her provincial life. The two team up for a fun day out on the town.

Along the way, they find out that they're both deep-cover changelings, and decide to switch roles for a little bit.

Equestria goes to Hell in a hoofbasket pretty darn quickly.