I have a 2008 Carriage Cameo. Regarding the he black "plastic" like covering on the bottom of the trailer that has pulled out of the screws. I would recommend repairing versus replacing. There are several products that do a good to great job for repairing depending on the location. If you have an area around screws then look at some stuff called CS Hyde UHMW Ultra High Molecular Weight Polyethelene Tape with Acrylic adhesive, 20 mil (Amazon). This is awesome stuff especially in a friction area like the bottom of a slide. The other stuff I use for general maintenance and tears is the 2" wide double glue black Gorilla tape. Whatever you use be sure the surface you are going to stick it to is clean. I use alcohol in a spray bottle to wipe down the surrounding area.
Regarding the slide, the old Carriage forum had information on the slides. I am guessing some parts should be obtainable from Lifestyle.
New forum:
http://www.carriage-lifestyle-owners.com/portal.php