I replaced 3 slide room toppers myself with material ordered from Tough Top Awnings. They claim you can do it with one person but I think that would be extremely difficult. It’s best with 2 people and 3 is even better. My total cost was $412 US so you can save a pile of money doing it yourself as it’s not difficult.
You can view my install on our blog. The first post (scroll down) is removal of the old toppers, seal treatment and preparation for the actual install on the next post dated the 15th.