I just finished an install of a 30 A Progressive Industry EMS on my 2015 24R. I'm a journeyman electrician. Using advice that I found on this forum I located the transfer switch for the shore AC and generator. The transfer switch was located under the big closet next to the fridge. I had to remove the drawer beneath the closet as well as an access panel beneath the drawer (remove six screws). I also removed one drawer bracket and the 1/4" wood bottom of the closet.
I pulled the 30A plug from the coach exterior to determine the color of the wire and used a meter to verify which line coming into the transfer box was from the 30A plug. I unwired the transfer switch and installed the EMS in series with the incoming shore power line. I added a short piece of 10/2 with ground on the load side of the EMS and wired it into the transfer switch.
I haven't mounted the digital display yet. I will probably put it in the closet above.
I put the EMS in line with the incoming shore power. There are possible issues with installing the EMS after the generator and shore power. I just want to protect myself from bad power coming into my coach from a campsite power box. The generator wiring is predictable and stable.
I hope this helps. This forum has so much valuable information.
2015 Forester 2401R MBS