Help: How to Lure a Cat Into a Pet Carrier

I've set up one of those big collapsible cat carriers in my bedroom
for the past month, with one of Mrs. Sweet Cheek's pillows, her
brushes, and some cat nip.

The cat nip was the only thing that got her to go completely in to the
cage, but interestingly, the attraction wore off in a matter of days.
She completely ignores the cat nip now, when I try to use it as a
lure.

I don't want to put tuna fish in my bedroom (I have the cage set up in
my room because she spends most of her time there); the smell would be
too unpleasant.

She hasn't been to a vet in years because she runs and scratches
pretty badly if you try to hold her for more than a few seconds. Is
the only way of luring her to throw a towel over her? Now how relaxed
will THAT be, when she has a four or five hour trip to her new home
ahead of her?

This problem is totally driving me crazy, so any help here or by email
would be greatly appreciated.