I would have loved to know how much my wandering affected the file size but I don't think it would be that bad - I wasn't mining, and world files seem a lot more bloated these days than they were in 1.7 and earlier.
But yeah I literally wandered for days. Sometimes I would walk through three or four rainstorms, just walking the whole time (and collecting pumpkins, I would go slightly off-course to avoid snow/sand so I could find pumpkins, but I wouldn't change course for any other reason), usually there'd be light votes so I wouldn't have to stop moving at all.