What exactly happens if you test positive before returning to US?

There has only been one person on this forum that I remember to recount what happened to someone in their family that caught it during a trip. That's why there are no responses to your questions. You could Google that subject and find some other accounts, the New York Times had story about this. And the rules always change so there is no definite way to say what will happen or what the regulations will be next year if or when the Rick Steve's tours actually resume. With outbreaks and shutdowns in certain destinations regularly happening there are no guarantees. I travelled this year for two weeks in Europe. I had designated one credit card to pay for the cost of a quarantine. Thankfully did not need to use it.
Here is one other account
https://www.cnn.com/travel/article/travelers-who-test-positive-for-covid-on-vacation/index.html

Yes, a person who tests positive has to find a place to stay. Yes, you have to isolate. I had to isolate for ten days, counting from onset of symptoms. Your vaccinated travel companions who test negative can go on home. Next, to fly home you need a letter from a doctor. That will be 11 days after your positive PCR, so be sure to get a PCR as quickly as possible. Your doctor's letter along with the positive test is how you can catch a plane.
Here is my account: https://community.ricksteves.com/travel-forum/covid19/positive-test-flying-to-the-states-what-do-you-do-personal-experience

Jazz’s CNN article goes to extremes, talks about evacuations, someone who died ( before vaccines), but that is highly unlikely today with people vaccinated and with 3rd shots. You might sleep for a couple of days, loose appetite, loose smell or taste for a day or so, a little fever, and then you just wait out your isolation time, log into work, read, etc.

I will also add that even though Rick did not run tours this year I'm sure his guides will be prepared for this eventuality and be able to help you figure things out with quarantine requirements, hotels and recommendations on how to get food in.

My plan for if I had tested positive in October in France was to go with Deliveroo for food. My hotel had said I could stay there if they had vacancies.

I also made sure I had "room" on my credit cards to charge 11+ days of extra hotel nights. In truth, if you are quarantined for 10 nights (not sure what the Spanish rules are), you'd spend day 11 getting a Dr note saying you've recovered from Covid and the earliest you could probably possibly leave is day 12 if that makes sense?

Thank you and thank you for referencing the post by Bets, all very helpful!

Just FYI I did buy an insurance policy thru Trawick that’d cover any expenses involved in having to isolate. It was like $50, so not at all expensive, and would reimburse for the costs involved in having to isolate if one were to test positive while abroad (hotel, food). With such a low premium, the peace of mind I get from knowing I have that policy is more than worth it!

I dont think the previous threads (and comments by Bets) addressed how return airline ticketing was handled. That is, did airlines allow re-booking, but only after the quarantine period, or would people (without insurance) be on the hook for a whole new one way ticket home?

It's expensive any time you change any return flight. I've done it several times for different reasons. This time I moved us up a fare class for more distance from others and for a more comfortable flight after the breakthroughs. I didn't need to change our dates.

First, in order to change a return, you must talk to an agent. Getting through to the US agents is nearly impossible unless you have status with your airline and the phone number reserved for the each status level. Otherwise, try calling the telephone number given for the country you are in. They are listed on the websites under Contact Us.

Next, you'll have to pay the difference in fare. You do not need to buy a new one-way ticket if you contacted the airline that you won't be flying. You can do that by text message or call the phone number listed for the country you are in. This is where having a travel agent would be helpful. You don't want to just miss your return flight and be considered a no-show.

i was told of this account from an acquaintance who traveled to Italy in the spring of 2021:

Traveler tested positive for COVID before returning home. He was placed in a COVID-quarantine hotel somewhere outside of Rome. Not allowed to leave the room for 2 weeks. With armed guards. The food was not great. i did not ask about costs. So, he did not have to find a place on his own!

Hopefully that experience wasn't too painful, Bets (thanks for sharing this info too, btw).

In the interests of being as prepared and informed as possible, I called up the airline I'll be flying later this month to ask the same question - what happens if we have to postpone our return. For the most part, their regular flight change rules apply. No different than if you'd just decided to call up and change your flight for any other reason such as simply wanting to stay longer, leave earlier, connect through a different city, or what have you.

Thankfully most of the airlines have pretty flexible rules nowadays, what with COVID and all. But one thing that seems to always apply is the fare difference - so hopefully your new dates 10 days later aren't much more expensive than your original dates were (and if they're cheaper? Airline usually pockets that difference).

I will confess, the transformer variant has me concerned about an increased risk of testing positive before the trip home.

That, and a few worrisome reports of how those who test positive are managed in some countries has me thinking about taking a handful of self test kits with me. Before I get the "official" reported to the government test, I will self test.

If I am positive, hunker in, put do not disturb sign on door and get touchless pizza delivery and keep testing till I pass.

Then take the test reported to the government.

Best double check with the hotel and see if they will mind?

I am wondering what happens in a 3 city trip. We are doing Venice, Florence and Rome. If we get COVID, in spite of being vaccinated, in Venice or Florence and our return flight leaves from Rome, are we on our own to get to Rome? Also, to people who have traveled on a Rick Steves' tour before, are the guides helpful in this type of situation? If we take home tests w/us and come up negative after quarantining for 3 or 4 days, can we leave quarantine?

@ Marcus.

Rick Steves Tours has not been in this position before, so it is hard to report on direct experience. Indirectly, I have seen and heard of guides going out of their way to assist with health issues of tour members. I also know that the Tour company contracts with a travel insurance company to provide support and advice for situations that come up. This policy doesn't cover the costs associated with health issues, but does provide people with expertise to help you with all arrangements. Here is the link to the PDF about this service. You can also find it in your tour documents. https://account.ricksteves.com/travel-guard.pdf

Another poster mentioned that he purchased coverage from his insurance company to cover possible costs. My particular travel insurance through my credit card provides up to $10,000 to cover quarantine (isolation) required by government authorities.

My particular travel insurance through my credit card provides up to
$10,000 to cover quarantine (isolation) required by government
authorities.

Very smart idea!!!