We have 3 matching braided oval rugs. We originally did it for warmth underfoot during winter camping, but the dogs have enjoyed them, too. They help keep the floor dry in bad weather, also.

We have a "spa" wood mat at the door for catching dirt or to use at the outdoor shower so feet don't get dirty when wet. We also use a cotton throw rug in front of the sink across from the stove. It used to be for one of our dogs who loved to sleep on it and also as a scuff prevention when we lowered the wardrobe (before we put little guard squares on the top edge that touches the floor) to keep it from scuffing the floor. We now scrunch up that rug between the lowered wardrobe and a removable wall cabinet which also sits on the floor for transport to keep the wardrobe, cabinet, and microwave from rubbing together when they all sit on the floor during travel.

I had carpet in my pup for warmth since I am a crazy friend who would camp in January  🙂

In the RV now it has carpet in 1/2 of it but I have a carpet runner in the main area to catch the dirt so I can shake it out when I want. 

No way.  Just a carpet mat at the front door.  We take 4-5 beach camping trips a year.  Between that and the dirt from other trips, we can sweep the floor several times a day.  Everyone has slippers for warm feet.  Systematically eliminating all the carpet in the home, too.  Dirt, allergies, etc., not worth it.

In our popup we have a runner from goucho to just under dinette and a throw rug at the door way.  Outside we use a repurposed BBQ grill grate set in a wood frame as an added step that allows dirt to fall thru