You are right about being difficult to do and it's not really necessary, especially if this is your first restoration.
Tub is removed through the top but the cooling lines are "gooed" to it. So to do that, the main gasket and side breaker strips first have to be removed, then the liner/copper coils, rusted floor and compressor all have to be lifted out together.
My advice is to leave the rusted floor alone and paint the machine. You should be able to treat beltline rust on the body without removing the liner and if the day ever comes that the rust on the floor becomes an issue, everything can still be removed without damaging any painted areas.