It's not an FR-3 specific solution but this is what we do. I reluctantly take the cat when we travel 3 or more days away. It's my daughter's pet and it has a good dose of Ferrell blood in her. I'm stuck with it since she's away at college. Well, back on topic....I put the litter box on the linoleum in the kitchen where it's an easy clean up when the cat tracks it out.
2010 Cedar Creek 5th Wheel 34SATS "The Beast"
2006 Ford F350 Lariat 6.0L Diesel
2003 Harley Heritage Softail "Hogzilla"
1988 Harley Softail Custom "The Fireman"
1986 Marriage to "Wifey" (patience of a saint)