Removing tub/adding walk in shower

As far as removing the tub, and putting in a shower pan, I have remodeled a couple of campers and trailers in my time, it is not hard to do, just need to be careful, and plan your steps well. I recently had to completely gut my bathroom due to a water leak, then fix the leak and install new flooring, plumbing, shower pan, shower surround, toilet, etc. All together it was about a week job, but, that was just a few hours here and there during the week, then all one day on the weekend.