The Atwood Air Command RV AC Unit part # AT15033-22 that you referenced would be an excellent choice for what you are looking for. It has a heat pump like you are wanting, a higher BTU rating of 15k, and it's designed for ducted applications like you have as well. view full answer...
While we do not have a custom fit trailer hitch receiver that is confirmed to fit your 2008 Country Coach Allure Motorhome you may be able to install a universal Class V hitch like the Curt Class 5 Universal Weld-on Hitch w/ Brackets - 2-1/2" Receiver - 44" Wide # C87CR which works with vehicle frames between 18" - 44" wide.
The # C87CR has a 2-1/2" receiver, a 2000lb tongue weight rating, and 20000lb trailer weight rating, but will need to be welded to the frame of your vehicle by a... view full answer...
If you currently have a Kwikee 42 Series electric step on your 1999 Country Coach Motorhome yes, the Lippert Kwikee 42 Series Electric Step # LC372779 that you referenced will bolt right up as a replacement using the same mounting attachments. view full answer...
For a brake controller I would recommend the Prodigy P2 Brake Controller part # 90885. This is our best selling brake controller because of how well it works and how easy it is to setup. This is a proportional brake controller that senses the amount of braking the tow vehicle is applying and applies a proportionate amount to the trailer brakes.
If you look anywhere online this brake controller is highly regarded as basically the best brake controller available.
I attached a review video... view full answer...