We are living in Bay Area, CA. Our house is 1950 ranch - 3b 1 1/2 bath. The Landry room has a separate toilet w/door and sink, a door that goes outside to the backyard - washer/dryer stackable and a separate space with a door for a furnace and water heater and another door going to the kitchen. Our plan is to convert that room in small bathroom - no tub just shower as a separate room and W/D outside.

Not sure from where to start and how much this would cost.
My initial plan is to move the furnace under the roof and put small instant water heater to use their space. How much that part of the project would cost?
Then close the two doors to the outside and kitchen, put a wall in the middle of laundry room and build a small bathroom. I don�t think there will be a lot of moving of the plumbing since the toilet and sink are facing each other and the shower can be installed there. However there will be some electrical work, gas lines etc. involved.

Thank you!