To go all the way to the top, it would be at least a full days work and possibly part of another day if you do it in place. Have done it on several masts laying on horses in a day. Figure out what a rigger's hourly charges are, if you are going to have someone else do it, and you'll have an idea. Wouldn't be hard to have a boat unit in labor alone.
Faster to do with SS or Monel pop rivets but you better have a super strong grip and work out for a couple of weeks before hand if you use a hand tool. Goes fast with a pneumatic riveter and a lot less pain. Don't like aluminum
pop rivets, have had too many fail. Have also installed them by drilling and tapping for machine screws. Takes more time but not too arduous.
The stamped aluminum
steps made out of aluminum tubing with foot area flattened are easy on the feet, and strong. Stainless ones made out of flat stock with a wider foot section also work but haven't seen them in years, probably because of cost to mfg. Don't like the folding ones as they are heavier, your foot can slip off easily, and didn't look comfortable for bare feet.