PlayPen
If you are camping with small children, really small, like crawling small, or small animals a playpen may be of a lot of benefit. With small kids this is a good way to let them roam and experience nature without having to watch them like a hawk while they wander off into the woods and say hi to a snake. You could also use it to create a barrier for the fire so your small child doesn't get too up close and personal with the flames.
If you have small animals these can be a good way to allow them to come on an adventure and not be tied to the grill the entire time. This may not be an option for larger dogs, I can't imagine the space it would take to put a playpen up for your mastiff.
They come in different shapes and sizes. Many of them are the typical playpen you would see for a child that have plastic walls and can encircle an area. They often times come with so many panels and you can expand by buying additional sets. There are also some that are designed specifically for animals. These tend to have other configurations that can include mesh on top so they can't jump out and meet that snake I mentioned earlier. They come in fabric, plastic, and metal. They can be a bit bulky so you will want to consider how much cargo space you can dedicate for this.