I am coming to Orlando on the weekend on the 17 for a week.
So a couple of “known” facts:
1) No matter what, you are coming back thru Orlando after Rainbow River which ever day you dive it cause it's on the way to WPB/JUP.
2) Enty & Exit dive times at BHB on Fri 22nd will be 10:15am to 11:15am and on Saturday 11:00am to Noon.
3) One way it's 4hrs from Rainbow River to West Palm. And it's 2:15 hrs from WPB to Orlando oneway. (I live in Orlando so I know those times)
Here's what I would do on those 3 days:
12/21
Lv Orlando 10am (You're on vacation, sleep in! )
Ar Rainbow river at Noon.
Lv Rainbow river at 4pm
Ar North Palm Bch Super 8 hotel at 8pm {~$90/nite}
12/22
Lv NPB at 7am, stop for breakfast at McD's arrive Jupiter Dive Center 8am for 3 tank dive including Deep Ledge & annual Lemon Shark mating season encounter. Purchase lobster license ($12) if you want to catch fresh seafood too.
Return to Super 8 at 4pm, Dinner at the world famous Brass Ring down the street, it will be wild that friday night.
12/23
Lv Super 8 at 9:30am, stop at ForceE shop along the way to get tank and flag rental and get to BHB early because it's a holiday weekend and parking will be tight
Lv BHB at 1pm and head back to Orlando by 4pm to wait for flights out the next day.
If you are staying free in Orlando, you could stay overnight Thurs and Lv Orlando at 6am on Friday morning, saving you one night hotel in NPB. Weather is always the wild card and you could flip BHB fri & sat but you might want to then look at a different boat option depending on what you want to see and do underwater. No matter what > pre-book everything, it's a holiday week and some boats are already nearly sold out.
Just my 2 cents or .00000000000012 of a bitcoin today.