Amtrak runs across the country, but relatively few people take it.
BTW, this site can be useful if you want to look up ferries in the U.S.:
Ferries in the United States: All Routes and Maps.
There are ferries that take passengers and cars, depending on the route. (Of course, you might need a car as well, depending on where you’re going/sitting.)
I’ve used it the most in the Pacific Northwest, where many communities are spread across peninsulas and islands. There’s also service to Canada.
I had a sit on an island off Seattle, Washington, and rented a car, for instance. Then I took a car ferry to my sit. I had flown across the country to Seattle while living on the East Coast at the time.
Sometimes, I rent cars even when loaned a car locally by a host. For example, I drove a host’s car in the Philadelphia area (in the Eastern state of Pennsylvania). Then when Ieaving, I had considered taking Amtrak to D.C. for a nonsit visit, but rental car pricing at the time was similar, so I drove instead. That allowed me more flexibility to stop along the way, plus I could toss my luggage in, door to door. After I arrived in D.C. and checked into a hotel, I returned the car at the airport. I used the subway and ride shares or walked till I left, because D.C. is easily navigable that way and parking can be a pain.
I did a sit in San Antonio, Texas, where the sit home was centrally located and I needed no car after flying in. On leaving, I rented a car to sightsee. I drove hundreds of miles from San Antonio and stopped at various places, staying in hotels. I ended up in Dallas, where I flew home from.
Depending on location and distance, you can be creative as well. Like in the U.K., I did two sits far apart. After my sit in London, I booked a sightseeing tour and saw a bunch of stuff before ending up in the town of my second sit. I just didn’t take the tour bus back to London. I had brought my baggage onto the tour bus (they had loads of room and the guide actually kindly offered to bring them aboard). I eventually left the tour bus in a central location and my hosts picked me up from there. Their home was easily walkable to the heart of town, too, so I didn’t need a car there.
This site shows one-way car and RV rentals that might interest folks, because they’re deeply discounted compared with regular rentals: $1 Relocation Cars, Camper, Motorhome & RV Rentals | Imoova.
The catch is, you have to pick up and drop off in specific locations where they need the vehicle back, within a specific window. These are not regular rentals where the renter decides locations and timing.
Generically, this is called dead-heading, similar to cruises where they need to reposition a ship.
They seem to run at lower speeds compared to trains in Europe, and are never on time, otherwise Amtrak is fine 
Trains are also a lot more expensive and not as comfortable. Well, at least all the trains I’ve been on, which have been in the eastern US. It just isn’t a fun and convenient way to travel here. Maybe for commuting, but not traveling in general, in my opinion.
I did a train commute for years and compared to sitting in rush hour traffic it was wonderful. But for longer travel, most choose to drive or fly.
Every sitter chooses for themselves, of course.
Many hosts won’t loan cars, and that’s their choice.
All countries have sits that won’t work out for everyone. THS isn’t the only option for hosts or sitters.
Dammed by faint praise. As a rule inter city fast trains in Europe are an entirely different experience to trains in the UK. Perversely and contrary to many expectations trains in Germany are not at all reliable.
“Starting April 29, 2025, Swiss Federal Railways (SBB) began forcing specific Deutsche Bahn (DB) trains to terminate at the Swiss border in Basel rather than traveling to inner Swiss destinations like Interlaken or Zurich. This measure aims to protect the Swiss rail network’s punctuality from chronic, heavy delays caused by arriving German trains.”
Amtrak works well in what is known as the “Northeast Corridor” Boston-New York-Philadelphia-Washington DC. There are also many low cost buses to travel between these cities, but as a regular service, there isn’t much in most other parts of the US. Each of those cities also has their own mass transit system extending to suburbs.
That’s exactly how I feel. I have been offered the use of a car twice and I have declined even when the hosts insisted that I should profit from it. I have hired cars and vans in lots of countries and driven on the right and left side of the road with no issues but if there was some kind of problem while I was in charge, I would hate it to have an impact on the hosts.
Why not though?
Probably because Americans are used to driving. It’s a huge country. Plus, if you have multiple people, driving is likely cheaper. And you’ll have your car wherever you want to go. Or you’ll have a rental and be able to go to more places without adhering to a schedule.
Americans love road trips and the freedom they allow. It’s part of many people’s childhood memories and they want to pass that on. We have a car culture.
Personally, I take trains for travel only when having or renting a car would be too much of a pain, like parking in NYC. Otherwise, I love driving and road trips are amazing to me.
I also take trains when I just want to relax while traveling abroad. No need to figure out anything. But driving to me in the U.S. is dead easy by comparison.
Yup, I enjoy the ease of trains in the U.K., the continent and Asia. But in the U.S., I love having the convenience of cars.
I have taken subways and buses in the U.S. for commuting purposes, but happily switched to remote work years back. Nowadays, the driving I’ve done has been for sits, but much more for road trips with my husband. It feels cozy with our dog.
This also might be worth noting for some folks:
In Italy, where I’m currently sitting for a friend, she rented such a car so we could do a big grocery shop for me, before she flew out. Even in places where there’s public transit, some things are just more convenient with a car (or maybe a moped or bicycle). Like if I want to buy a bunch of drinks, water or other heavy, bulky things, I don’t want to be lugging them. I’d use a car — mine or a rental — or get delivery.
Yeah @BonnyinBrighton I think it’s a size of country thing. We love getting around in the UK and Europe by train or bus. Locally in Brisbane where we live we have good public transport links. But Brisbane to Melbourne or Cairns or worse yet Perth? It’s a long way by bus or train and expensive. Like Maggie says we have a car culture here too and road tripping is part of that. Italian trains fantastic, yeah German not so much 
I agree @Maggie8K , London sit no need for a car, did use an uber to do a big grocery shop (I like to pick my own). Hired a car for one day to drive 4 hours round trip to collect some luggage we left at a previous sit. There are all kinds of ways to make things work depending where you are.
One of the things that might make it more compelling for some U.S. sitters: If you live in suburbs or rural areas, you will likely have a car. And it can be a nice change of pace to drive and sit in a city. Or of course, you could sit elsewhere for another change of setting.
For many Americans, it’s not a big deal to drive what say Europeans might consider a long distance. Some Americans even commute to work over long driving distances, or their jobs involve lots of driving.