Moisture in Intake Manifold, causing frozen throttle body

I live in Fairbanks, Alaska and its been seriously cold here (-30 to -40 F). Usually the Prius is a real cold-weather champ, but a couple weeks ago I went to turn on the car-- the engine fired up, immediately shut down and the car displayed the dreaded "Check Hybrid System" indicator. I repeated the ignition with similar results.

It was towed to the dealership, who diagnosed this problem: “Moisture condensing in the intake manifold caused cylinder misfire and caused the throttle to stick. A revised intake manifold is available to reduce, hopefully eliminate the problem. DTC’s P0300 multiple misfire and P0A0F failure to start & P2111 throttle stuck open. Thawing out vehicle restored normal operation. Intake manifold has a lot of moisture in it.”

The dealership wants to install a "revised" intake manifold for $900. I've done extensive research online and have found very few other examples where an intake manifold moisture issue is causing a throttle body to freeze. The intake manifold suggested is part # 1712037054.

For background: I have a block heater and I plug the car in for 2-3 hours (if its below 20 degrees F) before using.

A few questions:

A) Doesn't my Prius already have this "revised" intake manifold (since its a 2013, and the "revised" design was released in 2012?) Where would I find out the part number of my OEM intake manifold?

B) Do I really need this revised manifold to solve my problem?

B) Assuming I decide to forego this expensive and potentially unnecessary repair, how should I prevent moisture from building up in my Intake manifold? My suspicion is:
--Avoid shorter trips-- turn the car on and let it fully warm up before turning the ICE off
--Ensure the engine has been plugged in at least 2 hours in cold temperatures
--A friend of mine suggested putting Isopropyl alcohol in the gas tank to reduce water content. I've done some internet research but am quite skeptical-- it seems a product like HEET would be more effective.

C) This is my sole automobile and I use it often for wilderness adventures in the Alaskan Interior. It is usually exceptionally reliable but with this potentially chronic issue I'm worried. This weekend I'll be 2 hours away from Fairbanks and leaving the car out for two nights in -20 conditions. I am worried about returning to a car with a frozen TB. I'll have friends cars there to help warm mine up in case of any issue (or if I need a jump). How would you deal with this issue if it repeated itself and you were off the grid?

 

Thanks for the help.

Also, I forgot to mention: car is a 2013 with 92k miles.

I'm definitely not taking my car into the dealership to the get a different IM.

My plan is to ride out this winter, then do a full IM/ EGR cleaning and maintenance when warmer weather comes. I may or may not upgrade to the "cold weather" intake manifold depending on what else I learn about it.

Still makes me wonder what I can do now, this winter, to prevent moisture from building up. I'm going to avoid shorter trips. Is there anything else?

 

I do have a block and oil pan heater. This is especially critical since I park outside and don't have a garage. I also have foam covering my front grill -- I only did this recently and its made a significant difference.

My current plan is to order the Cold Weather Intake and install this summer. Even though it may not be essential, it strikes me as a decent insurance policy. I'll do some preventative maintenance while I'm in there.

So far the problem has not happened again. I've been very diligent to keep the car plugged in at least 2 hours when its below -20, and to not shut it off after driving short distances.