That's the way to do it if you have the time. You end up with essentially a new trailer for a fraction of the cost as long as the crossmembers and main frame rails are good.
Also, if you do it, consider using 3/8" torx floor screws instead the 3/16" they normally use. It makes a BIG difference.
ours is coming out beautiful couple thousand on trailer and a few thousand on aluminum wish my brother in law let me sand blast and paint it first but as soon as I told him I can do it he wanted me to start the decking right then lol
Hardest part is everything is bent and not squared from all the abuse over the years so there no template making everything had to be measured separately especially those container chains that come up on the sides
