While researching portable EMS/surge protectors, I found that a lot of folks here recommend hard wiring one in after the transfer switch to protect against generator surge as well. I lift up the bed and see that I have two automatic transfer switches - a MagneTek ATS 100 and a Lyght LPT50CA. Is there a simple explanation?
Yes. Two ATS switches for two different purposes.
One (LPT50CA) switches between shore power and generator.
The other (ATS 100) switches power supply to the inverter sub-panel between either direct AC power from main panel, or AC power produced by inverter (when shore power or generator is not available).
You should have a diagram similar to the one linked below in your Owner's Manual.
https://www.foreforums.com/index.php?action=media;sa=media;in=3269
Some Foretravel models have two transfer switches and those that do are explained below. Those with only one transfer switch use inverter/charger's internal transfer switch, with the disadvantage of limiting amps when not inverting.