This is probably the best type of mouse trap I've seen yet. It's great for long or short term Rv storage & doesn't require constant monitoring. This video, although in Spanish shows the mechanics of making your own trap & is the best idea I've seen yet. There are many YouTube videos on different construction concepts, but they all work pretty much the same.
https://www.youtube.com/watch?v=C8baebZY18s
3-5 inches of Water or anti-freeze can be used in the bottom of the bucket. But Remember, if you are in a very cold weather environment, & you use water, the little guys will just be ice skating & you'll have to end their existence in some other way yourself.