At that price for food, airfare, and the cruise, I would still go. Not sure where else you could go for that price without spending a lot of time driving. My other thought was Nashville.
Agree about considering still going on the cruise. You say you have never been to Turks and Caicos before and the private islands are nice. Lots of free entertainment on the cruise as well.
Sedona?
Since you’ve already paid and have the option for a full refund, maybe check with the cruise company about what compensation they may be offering for passengers who still opt to go on the cruise? That may sweeten the deal so you have more money to buy momentos or nicer shore excursions. Just another thought, if you MAY still cruise.
Cruise price sounds amazing. Price for 1 night in T&C can be over 500, so sounds like you’ve got a great deal.
If you don’t want to do that, agree with others that Tahoe is not good that time of year.
Maybe Sedona as second choice, or Santa Fe? The Balloon Festival is in October in Albuquerque , and is pretty spectacular.
Scottsdale, AZ area? H went to there a conference a number of years ago and I tagged along. The conference was at The Boulders, which is a lovely resort/spa. While H was at the conference, I went hiking in the area (the hotel arranged for a guide). There’s also a great golf course. Frank Lloyd Wright’s Taliesin West is nearby (H and I did a tour). I also enjoyed the Desert Bontanic Garden and Heard Museum (focus on Native American art)–I loved them both.
If you go to Scottsdale, you aren’t far from the MIM…Musical Instrument Museum…which is a must see in the area. Agree, weather should be the sweet spot of mild days and cooler nights. Great for walking. The Desert Botanical Gardens are terrific. Great hiking near there as well.
November is still technically hurricane season (retired to Tampa and it’s local news, as is Cuba) but your cruise with a Bahamas substitution sounds wonderful for a getaway. Nassau was (and likely still is) a great city- our two land trips there included fun walking around town. At your cost I doubt you could find a less hassle free trip. Our only cruise was to Alaska but plenty of walking can be done on a ship and in towns visited. We were never into beach sitting for any of our island land vacations. It is interesting to glimpse local culture, even in the tourist areas.
Remember the time it takes to get places, their weather and the need for a rental car, finding restaurants et al in any city visit. Costa Rica is nice- but for that price (and time limitations)???
Not needing to drive during the trip and checking into one room with a whole ship to explore along with merely walking onshore can be a delightful change of pace. Plus food/dining without needing planning/extra costs is a bonus.
Free shows and people watching on a boat. The price you have would be hard to come close to for most getaways. Cuba can be a separate trip if you decide to do that.
Thank you for all the wonderful replies. I really like the Costa Rica idea. I found a beautiful resort but the flights and local transport are an issue and definitely will cost more. Arizona and Key West could be an option as well. A friend suggested Dublin but not sure how the weather would be in November.
I agree it is hard to beat the price we paid for the cruise. We booked extra early during a sale end of last year. We wanted to do Cuba for a while, and the easiest way was to do a cruise. With the new travel restrictions, we would not be able to fly there either.
We have to put the cruise back in as an option. They are giving us $200 to spend on board. So that could buy us a few Cuba Libres and Mojitos to drown our sorrows. ; ), It is an older ship so they don’t have all the bells and whistles to keep people busy otherwise.
What about going to Italy or Spain? Norwegian airline has very good airfares to Europe, 400-600. Hotel rooms in Nov should be inexpensive. We just came back from Spain. The trip was planned out by D1. We were able to stay at some great hotels (4-5 stars) for 150-200/night. You could get a glass of wine for $2. 
Another idea is the Azores. Temperate weather year round, quicker trip than European mainland, trendy destination.
Even the older ships should have lots going on. That deal seems hard to pass up if everything is already in place at such a great price.Good luck with the decision!
Given how inexpensive the cruise is, maybe you might stick to the original plan and later go out for a splurge meal or an overnight at a fancy hotel near home to commemorate the milestone birthday. Or you could use the extra on-board credit for some meals at specialty restaurants. Some ships have multi-course meals with wine pairings that are quite indulgent.
I love DIY travel and I also love the relaxation that can come with cruising.
(side note: CC people are AMAZING at trip planning. I’m waiting for the thread where a poster can say, “I have $2k and a week. I’d like a beach vacation that is not a cruise and my home base is ____. Plan my trip for me” - and have someone do it!
What about Puerto Rico? You should be able to find a great flight out of NYC. Some beach, some sightseeing and some nature.
Also, you could look for the cheapest flights in to Europe and go somewhere for a week. We are just booking a flight to Madrid that is $275 round trip for the end of August out of NYC. I’m sure you could find something great.
Arizona including Sedona would be a nice trip for hiking. Could add on Grand Canyon or the Phoenix area.
Although cruise ships are no longer allowed to dock, I believe that under the category 'Support for The Cuban People", you can still travel to Cuba, Delta operates flights from Atlanta; staying in AirBnB, fincas; eating in paladars, shopping local, offering support to religious institutions, taking private cooking classes etc. all contribute to the support of the Cuban people. Avoid government owned shops, restaurants and hotels
Maybe by the time of your trip the ban will be lifted.