She should be fine for the four hours.  I had my first cat w/ me for what
was supposed to be a little under 3 hours one New Year's.  But there was a
snowstorm & the drive took me at least 4 hours.  I think she simply slept
through most of the ride...   If healthy, a cat can quite easily make do
w/out a litter box & food for that amount of time.  Even if you add on a
half hour of transit time to each end of the trip, she should be okay.

I take it the bus co. allows a cat carrier (w/ a cat in it)?  I hope.

Cathy

Cats can go on car rides for that long... so should not be a problem..she'll
probably sleep..just DO NOT take her out no matter what--strange places,
noises, etc. would make her run away & hide.  Make sure that bus will let
you on with her.

Make sure to call and make complete plans with the bus company way in
advance. Even if they allow you to bring her on the bus with you, they may
want you to buy an extra ticket for the seat, or they may have rules about
papers, types of carrier, etc.

As the others have said, you first need to make sure that you will be
permitted to take your cat on the bus.  I did a great deal of traveling with
my cats, both by car and by plane (with the cat in the cabin under the seat
in front of me).  I made long trips without any problems.  I also took a cat
on the train for several extended trips.  However, "rules" changed and
trains would no longer permit pets.  At that time, I looked into the
possibility of bus transportation -- and they also did not permit pets.  So,
*make sure* that the bus line you plan to use will permit pets before you go
any further with your arrangements.  If they do permit it, cats can travel
just fine.  Send me email if you would like for me to describe some of the
preparations I made when traveling with my cats.  (The e-mail address
attached to this is valid except that you need to"take-out-the-litter.")

MaryL
Holiday safety tips for cats:
http://community-2.webtv.net/getcathelp/holidaysafety/

When I had to take Oscar cross-country in the car, I found that she *wouldn't*
use the litterbox or eat.  I guess all of the weirdness was just too much.  My
guess is that she'll have no problem "holding it" for that long; she'll be too
nervous to pee, anyway.

My dad works for Greyhound and I am sorry to tell you that they do not allow
any animals other than certified service animals on their buses. Neither
does Peter Pan. You will have to find alternative transportation or find a
cat sitter.

SueNY