I just finished a major repair and renovation of our MH which included removing the carpet from the bedroom, passenger/entry steps and under the driver's seat. I also pitched the uncomfortable sleeper sofa, pulled the carpet off the slide and extended the slide platform to accommodate a recliner.
I learned a "couple" of things. They lay the carpet before putting in cabinets, beds and appliances. You have to use a razor knife and cut the carpet from around things. They use a million staples and the carpet hides a lot of gaps and unsquare corners. Most of my carpet had a pad as well as the carpet and left some rather large gaps after removal. I did put down subfloor to make up the difference. Be prepared for some creative trim work. In the bedroom, I had to put a piece of quarter round between the floor and the bottom of the slide to fill a big gap when the slide was out.
I put down the Allure Ultra although it says not for RV use. I have a contractor friend who did his MH with it and has not had issues. Others on the forum have used Allure with no problems. The consensus seems to be that since the runs are short compared to a house size room the shrinking and expanding from temperature is minimal. I also used silicon under the flooring on the advise of my contractor friend who said it will allow the floor to move.