Towards the end of Ch. 6 (VI) we find the answer to this question when Victor says,
"Henry proposed a pedestrian tour in the environs of Ingolstadt, that I might bid a personal farewell to the country I had so long inhabited."
Victor then says he agreed to go because he likes to exercise and that Clerval (Henry's last name the name by which Victor also refers to him sometimes) is always his favorite companion to take walks with.
Apparently this "walk" lasts about two weeks, according to Victor. During this timeframe Victor's mood continues to improve a great deal, his health seems to be better, and he is reminded of how secluded he had truly been during his studies. He really seems to enjoy being able to spend this time with his closest friend. This, coupled with his renewed appreciation for nature, makes him feel better, both physically and emotionally.