Designing Kitchens and Bathrooms - replacing damaged bath floor

I have a hundred year old house. The floor in the bath has been replaced with plywood. Due to moisture it has rotted.
I want to tile the floor. How do I remove the floor and what do I need to do next? the sink and toilet have already been removed. Also the tub is cast iron how and should I remove it? Thank you in advance for any help.

Did this same thing 2+ years ago @ my prior house of same age as yours. Tub was a claw foot so it was easy to disconnect and turn on its side to slide through the 28" door. If yours is not the same, you will have to do more work to disconnect but should still be able to slide out the door. Measure the thickness of the floor, set te circular saw to just a hair longer and have at it. The house should be baloon construction so you will be able to remove the remaining flooring to the exterior walls with a pry bar. Inside walls you made need to cut flush with a saws all. When everything is removed check all old plumbing. I found a lot of broken sodder fittings do to floor flex. All repaired dropped down new subfloor [2 layers of 1/2" ply] and then put vinyl over [new I was planning to move]. This was the only bath in the house and I completed the work in 3.5 days [Started Friday night removing all the fixtures and reinstalled everything with the last screw done at 11:49 pm Monday]. The wife gave me one weekend to complete the project & I was handsomely rewarded. :)

Doug