Hello Debra,
As far as covers for the ramps, someone suggested to me to use old tube
socks for a cheap and easy way to cover those wire ramps.  Also a web
site sells ramp covers that look really nice and soft.  They are called
For Ferrets Only, their products are a little pricey but are wonderful
and of the highest quality.
 
I sympathize with you, I have 7 litter boxes in various places in and out
of the cage and still am cleaning up poop from misses and strange spots.
I have put down square remnants of linoleum under all boxes and the
frequent poop spots.  I have also used something called Pooch Pads to lay
down for the messies, I got it them at Petsmart and they are washable
and very absorbent.  I have found that good old cheap and easy newspaper
seems to work the best.  I have invested in a lot of velcro, cage clips
and clamps from the hardware stores to prevent migrating of the litter
boxes, linoleum, pooch pads, newspapers and other various movable objects.
I have also tried to let the fuzzies tell me where the good poop spots
are and then try to equip that spot with litter box and the trappings.
Some of the corners and spots I have tried to eliminate by putting
something there, (furniture, pillows, bedding, sleep sacks, ferret beds
ect)  They usually won't go where they sleep, but sometimes they surprise
you.
 
I don't like throw rugs either, due to the rubber backing and the chance
of stepping on the little ferts burrowed underneath.
 
Good luck and remember the key ideas are to think creatively and safe!
 
Suzi and da' slinkies Cheech, Chong, Goose, Ruby and Mookie
[Posted in FML issue 3699]