I found this to be an interesting question... even though a few months ago
I would have thought it weird.  I have lived in a two story dwelling with
ferrets for 15 years.  The ferrets in our household have had to maneuver up
and down 14 stairs (7 and then a landing and then 7 again.) It was taken as
a matter of fact that ferrets do not have troubles with stairs, because,
well frankly, that's all they have ever had to deal with in my home.  Keep
in mind that I have stairs that have open areas that allow them to overlook
a distance of about 8-9 feet.  None have ever leapt off.  They just like to
look.
 
Late last year, I fostered, then adopted, a wonderful but misunderstood
girl (severe biter) who I named Thalia... after the muse of comedy.  Thalia
was the first ferret that I have ever had the pleasure of knowing, that did
not understand the concept of so many stairs.  In her previous foster home,
she had 4 to maneuver and she managed just fine.  I would do things like
put her on the landing in between the two sets of stairs so that she would
have to be forced to choose which way to go.  She always went up, and once
up, would never come back down.  When her other ferret buddies, scooted
down the stairs, she always hung behind, watching them go and drape her
head over the edge like she was disheartened they had abandoned her.
 
We didn't give up on her though but continued to carry her up and down the
stairs so that she could see that there were great things to explore on the
level below.  Last month, or approximately 3 months later, we found Thalia
downstairs.  My hubby asked if I had brought her down.  I said no.  It was
then we realized the connection had been made.  What remains a funny story
for us is that, for that entire day, Thalia kept running up and down the
stairs.  It was as if they had become the greatest open door to her in a
long time.  "Look ma, look what I can do!" "Are you watching, are you
watching!?"
 
Imagine, if you can, the sound her little feet make on the stairs, like
all their little feet, as we have no carpet anywhere in our home.  Going
down the stairs... budoop, budoop, budoop, budoop, budoop, budoop, budoop,
chick, chick, chick, [on the landing] budoop, budoop, budoop, budoop,
budoop, budoop, budoop, chick, chick, chick, chick, chick... [And when you
say this make sure you sound like you are doing music scales...]  Going
up... budUP, budUP, budUP, budUP, budUP, budUP, budUP, chuck chuck chuck
[on the landing] budUP, budUP, budUP, budUP, budUP, budUP, budUP, chuck,
chuck, chuck.... [Different sound comes from their nails on the floor
upstairs.] The speed in which you hear this is directly related to whom is
actually doing the ascending or descending.  Ping is really fast but you
can add the thump of her tail in between, and Chook is more casual about
it, but he also drags his feet when he walks.  Some are lighter on their
feet, like Bear, and some make pauses as they go, checking each stair for
interesting morsels, like Cherokee and Oh-Oh.
 
So, to answer the question of stairs, I don't think anyone would have
any problems whatsoever.
 
betty and her blur o'fur
[Posted in FML issue 3013]