Here's what we do. As part of winterizing our T-2499, I steam clean the carpet and furniture. We have an upright steam cleaner with a hand attachment that makes it easy to navigate the narrow confines of the unit. After each trip I vacuum the carpet, lightly, mist it with a dilute cleaner, and then rub the carpet with a clean towel. When on the road I keep a spray bottle of dilute cleaner and a soft towel handy to blot up spills and stains.
This works well for us. If you keep up with the stains, the rest is easy and the carpet stays nice.
Hope this helps.
2005 Sunline Solaris SE T-2499
2006 Chevy 2500HD D/A