How long/heavy is your Keystone Larado?
Your Duramax already has sway bars. I assume you are talking about sway control on your hitch? With the length/weight of my crew cab long bed Duramax 2500 to the length/weight of my trailer I never used sway control on my hitch and never had ANY trailer swaying issues. Not even in pretty heavy winds. The length / weight of your Duramax vs the length/weight of your trailer will determine how much your trailer is able to throw your Duramax around.
I have a Duramax 2500 crew cab long bed. It pulls my 26' Coachman Captiva fine without a weight distributing hitch... but pulls it much better/smoother with a weight distributing hitch. With the weight distributing hitch properly adjusted I never even knew the trailer was back there.
The OEM receiver on my Duramax was plenty heavy duty for the weight distribution hitch I used. I can't imagine any need to replace the factory receiver on 2500 Duramax even on 30' trailers and over.
Plug your trailer into a 30amp outlet in a campground via a 50amp/30amp adapter. Turn on both AC's and start the microwave. The 30amp breaker will trip on the campsite outlet. No harm / no foul. Just turn off one of the AC's and reset the outlet breaker. You will be back off and running! Use the 50/30 adapter, you will be fine!
I think whole trailer surge suppressors are a complete waste of money! If you have a sensitive device like a laptop or a TV then use a cheap plug in surge suppressor. The trailer wide protecting surge suppressors are are a complete rip off and won't protect your laptop as well as an outlet type surge suppressor.