I'll add to my previous post. The coach batteries are under the entry steps on Sunseekers and Foresters, and maybe also on Lexingtons. It's easy and simple to run a cable from the battteries to the manual switch. On Class A's and trailers, batteries are remote from the entry door, so a switch controlling a solenoid may make more sense than running cables.
A short cable run with a manual switch is nice and simple. The switch is marine rated for salt water service and seems to be heavy duty. Not having a solenoid eliminates a possible failure point. I like simple and stout.