I had a fan motor burn up last year, and changed it on top of the trailer. The fan was destroyed by low voltage in the park we were staying in. I was fortunate to get a donor air conditioner from a friend who had to replace his unit because it quit cooling.
It certainly is doable, but not a chore that I would like to do again.
"To compel a man to subsidize with his taxes the propagation of ideas which he disbelieves and abhors is sinful and tyrannical."-- Thomas Jefferson