This is what I did when we did a gut job for our master bath.

Start by finding a contractor because the labor will set the tone for your budget. Then start building a board. Since you're going to keep your cabinets, find the next larger expense which is the counter and tub then the tile. Fixtures for lighting and plumbing come next, then window treatment and then paint color. I suggest leaving the paint color until last so you can pull a color from the window treatment, tile or even your towels and accessories.

** I didn't build a board, but I should have. Building a board gives you the benefit of a visual to see if the flow of all your choices works.

Before you do any of that though, do a little reading in the bathroom forum about what it takes to do some of the jobs you've mentioned the most important being the shower work. Get to know the products available, what works the best and why so you are knowledgeable enough to know what questions to ask and if the answers will meet what you need to be done. And be prepared or willing to be around when the crew is working. Don't get in the way but make your presense known, check in, ask questions. There was a couple of times I caught things that weren't right or that I at least wanted differently than it was being done. So educate yourself, supervise and don't be afraid to ask questions when you don't understand.

A lot of people have trouble finding a good contractor. My trick was to ask someone in the construction trade for a referral. The tile store referred a tile guy, who then referred a Master plumber who typically worked on new builds. He had a buddy who was a fantastic carpenter and General Contractor. They typically won't refer someone unless they know their good and both of the guys I mentioned above wanted feedback if I ran into problems.

ETA: I forgot to say that it's helpful to find inspiration pictures to help you with style and a direction. And I'm not sure how busy the bath forum is now a days but it would be a good idea for you to cross post there as well. The pros and diyers were the bomb when I was working on our project. I learned so much from them!

You don't mention plumbing fixtures, like shower heads, faucets, sprays, shower valves. Those items can really get costly.

Ferguson is a good place to see the variety of stuff, but I found that they were obnoxious to deal with.

Good luck! It looks like a nice large room. DH's senior work partner did a similar type of job and it came out great.

I was just telling DH we probably need to re-do our main/hall bath this year. It was last refreshed 10 years ago sort of a temporary measure. The floor was recently re-done with black and white pinwheel tile, but we will need to change out the drywall and shower tile. But our room is small and I'll probably never have a freestanding or claw foot tub in this house unless we do an addition someday. We don't really plan to move unless something comes up that we cannot pass up. We are in a great location as far as our work is concerned, and our neighborhood is the "hot" neighborhood right now.

I found a lot of ideas here and on the bath forum. I don't know if the bath forum gets as much activity. I did spend some time at the big box stores looking at fixtures that were recommended here, and then at a couple of tile stores, too.

Right now, we would plan to "retro-renovate" the bath with putting back color tile. Don't think I could convince DH on pink, but blue, aqua, or yellow are good possibilities. As I mentioned, we are not moving because someone would rip out that "dated" bathroom.

Our former neighbor is a contractor and excellent tiler, so at least we feel good with him. We're not moving anything.