Install additional 110 volt outlet in RV

Thanks for the replies to date folks. What I'm really looking to do is use your typical old work box with the little tabs that flip out...but the wall is about 2" thick and the screws which are included with the flip out fins will not accommodate the wall thickness. I don't like the looks of the self-contained plugs -- lets face it, my kids will be plugging and unplugging stuff and they're not always kind to outlets and pull pretty hard. I have not used the self contained version, but would it really stay in place as firmly as your traditional old work electrical box?

Once again, thanks for all the quick replies folks. Looks like I have a weekend project now!