New AC in the Roadtrek - DIY complete steps

[UPDATE: We installed unit #3, an LG LW8016ER, in Feb 2022 which is still working OK. We do not recommend these Frigidaire ACs. TWO of the Frigidaire AC units failed on us after 6 months of use each. The compressors and fans were turning on but no cold. The second one was model FFRA081ZAE . These window AC's are cheap and less expensive than the cost of a repair, so unfortunately we did not obtain a professional diagnosis of what malfunctioned. All of these units were subjected to long drives and lots of off-road vibration and bouncing, along with being bombarded by hours of dust and sometimes small pebbles. On the second unit failure we heard a loud "hissing" sound which could have indicated a freon leak. FYI no looseness or movement was noticed in the units themselves as a result of my install method...our RV just has an extremely harsh ride in the rear.

I'm not making a follow-up video for these latest installs but I've updated the recommended materials below based on how the original materials list held up over 10 months on the road.]
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[Original post, edited]
Here's how to replace the air conditioner in an almost-vintage Chevy based Roadtrek class B RV - the Roadtrek 200 Versatile, year 2000. Residential window air conditioners (not RV roof air conditioners) will fit in these RV's.

Links to some tools and materials:

AC shown here: Frigidaire FFRA0811U1 [NOTE: this one failed after 10 months, replaced under warranty with a different model sent to me by Frigidaire, model FFRA081ZAE, which later also failed]
Silco 4500 RTV caulk - Very good. https://www.amazon.com/gp/product/B01...
Wellnuts (to secure the roof hatch lid) https://www.amazon.com/gp/product/B00...
weatherstrip - for the roof hatch lid https://www.amazon.com/gp/product/B00...
weatherstrip - to put on the floor under the new AC - This did flatten out a lot. https://www.amazon.com/gp/product/B01...
VHB tape 4950 [NOTE: How did this VHB hold up when I replaced the first Frigidaire AC under warranty? Fine! And it wasn't that difficult to remove by applying some prying force. VHB doesn't like peeling forces. The remaining tape could be scraped off with a razor blade. On the second install I used smaller pieces on the rear fins just in case I'll need to remove it again]
Flex Tape: NOT RECOMMENDED for waterproofing CONTRARY to this video; the adhesive runs and fails in the hot roof compartment and it's hard to clean up. Flex tape https://www.amazon.com/Flex-Tape-Rubb...
On second install, to weather-proof the extension cord junction inside the roof I'm simply making sure the low point on the joined cables is NOT where the cables come together. Any water dripping down the walls of the roof compartment will flow to the floor. I lashed the combined cables to the side of the AC with a wire and zip ties. This isn't a good set-up if you frequently need to open the roof area in pouring rain, but I don't anticipate that happening.

Aluminum bar 1.5 inches wide X 1/8 inch
"L" brackets, 4, stainless steel
Simpson strongtie "L" brackets, 4
ABS plastic sheet https://www.amazon.com/gp/product/B00...
Cable organizer clips - BAD in this application! Use zip ties with VHB under some zip tie anchors, or use other screw-down cable clamps https://www.amazon.com/gp/product/B07...
Leviton replacement electric plug - used in roof area https://www.amazon.com/gp/product/B00...
Leviton replacement electric plug - used inside cabinetry https://www.amazon.com/gp/product/B00...
extension cord https://www.homedepot.com/p/Husky-25-...
long-handled urethane knife https://www.amazon.com/gp/product/B00...
XL blades for urethane knife https://www.amazon.com/gp/product/B00...
Amazing goop - held very well attaching AC foam to tops of the rear fins etc. Adheres well to ABS plastic. https://www.amazon.com/gp/product/B01...
AC foam https://www.amazon.com/gp/product/B01...