Why does the family decide to spend a day in the country in the metamorphosis?

After Gregor has died and freed his family of his horrendous presence, they can now take a rest for a while and get back to their normal lives. Gregor had been a burden for them in every way, as he stopped providing for them because of his new condition. Because of him, they couldn't leave the apartment and find a smaller one. Because of him, they had to rent a part of the apartment. His unwilling transformation had changed their lives for the worse. Now that he's gone, they have a hope for a better life. They even start pondering on their daughter's potential marriage.