This is the other wall. Shower/Tub has two shower heads.

For a jetted tub used as a shower, it has to have an integral tile flange. That allows the wall cladding to overhang and any water that hits the wall to not go behind your walls. There aren't that many in that size that are inexpensive. It will need a specialized drain, and, if you want to spend any time in the tub, a supplemental heater so the water doesn't cool off so fast. Since it's a tub/shower, the wall cladding will need to be redone to be waterproof into the tub. It's possible, if the build is recent, and it was done with the proper vapor barrier behind it, that only one row of the tile would need to be pulled in order to replace the tub. But, I wouldn't count on that. I'd count on having to replace all of the wall cladding in the alcove. That can be as cheap as a plastic surround for around $100 or cheap tile with the proper vapor barrier for probably $150 or so. The first is the easiest and the least chance of leaking. The second will read as more upscale, but you have to be sure your contractor understands about the vapor barrier and correct materials to use to tile this (NOT mastic.) And since you have that torn out, it would be foolish to try to keep your current control valves for the bath unless they are also very new. New safety standards are in place for anti scald mechanisms. So, you will need a new shower/bath faucet and valve. Then you will need the electrical line run from the panel to the location for the whirlpool pump and supplemental heater. That location is usually opposite the drain side of the tub. You will need to be able to site an access panel that is removable to be able to get to the electrical innards here. That can be from an adjacent room, or from a hidden panel on the tub itself. All in all, you might be able to get all of the needed materials for 2-3K if you shop the box stores carefully and find some bargains. The danger to that is that if you are inexperienced, you don't know if you're buying quality or crap. They sell both. And that's one reason that it would be simpler to let the pro pick the products after you tell him the features that you want. Then you've got to pay the contractor labor to install all of that. The electrician's price will depend on how difficult it will be to access the panel and run the wire to the location. For that, it's a really good thing you are on a crawlspace! That makes it cheaper for both the electrician and the plumber. On the whole, I'd expect your project to cost between 5-7K, depending on location, and if you have no DIY skills to bring to the table and have to hire professionals for the whole job. And be sure that you hire someone that is licensed and insured to be in your home, and will pull the proper permits to get the job inspected with your code office. Some handyman guy isn't licensed to do electrical of that nature, and while he might be able to do the demo and get the tub in place and glue on the plastic surround, it's unlikely that he'll have the right insurance to deal with a large job like that, and thus probably wont' want to pull permits and be inspected. They are usually limited to smaller jobs like simple fixture replacements like a faucet or light. Which this isn't. Just remember, you are doing a project that combines electricity and water. You really have to know what you're doing here! A small General Contractor should be able to do the complete job, and also carry the needed papers. And he should have no problem with the code guys coming in to inspect his work either. If he does, then he's not the right person for the job.

I think it really depends on if you are a bath person or not. Personally, when looking at houses a bath was not a “downside” unless it robbed space from a full sized shower, leaving either no shower or something the size of an old broom closet. I’d take a shower over a bath any day. All that said, I don’t take baths, and my husband who does is happy using the one in the bathroom down the hall. If you are someone who takes baths, then I would look at doing a tub/shower combo (an alcove tub like mentioned above)...you can do tile walls and even a glass enclosure to make it look a little prettier. If you have the space, or are tall, maybe see if you can put in a 6’ tub/shower? And because of your arthritis I recommend avoiding drop in/deep soaker tubs and such anyway. They can feel luxurious for sure but they are more difficult to get in and out of so that may factor in during a flare or down the road. For closet space, I ditto the recommendation to look at PAX from Ikea. I like walk in closets, but if you are going to sacrifice walk in closets I would go for PAX over a built in reach in closet. They allow a lot more flexibility with how you arrange things in your rooms, are very functional/customizable, and they look nice!

The overwhelming majority of demographics for your complex would prefer a great shower versus a mediocre tub/shower. Aging people who want to age in place need a shower - and as large as possible because stepping over a tub becomes increasingly problematic. Design with both function (bench and as many grab bars as possible to be reachable anywhere in the shower). While many older people are nimble up to a certain point, there are also periods when they might not be able to bathe and among my senior friends many have given up baths even if they previously enjoyed them because of difficulty of getting up from the tub. While you might lose a buyer who absolutely demands a tub in the master, the greater number will appreciate a great shower. And, if someone really wants a tub experience as critical, chances are they would prefer a larger soaking experience versus a tub/shower combo which doesn't provide the best experience for bathing or showering.