Modern Commentary
I mean, Kimberly negotiated for the new apartment and got him the job that will let him pay rent. If it wasn't for her intervention, he wouldn't have a floor to sleep on, let alone a bed. So carrying a few boxes upstairs is -

Upstairs? Y'know, I had always envisioned the two-bedroom apartment being a floor or two above their old place. I'm not sure that I ever told Isabel, and I'm not sure we ever officially say the building has a second floor.
Stairs are kind of a hassle. Both for the characters and for the artist. - Terrence