I proposed not long ago (but importantly, before Paralives came out, so it’s not taken from there) a system of travel between cities by train or car. Nothing on a massive scale, no permanently operating stations or airports, and definitely no customs inspections, border controls, and all that! But now I want to formulate this as a separate suggestion with details.
How I see it to make it interesting:
BY CAR
- For car travel, a separate location is created in the form of a long narrow highway. Players enter it through a short loading screen and leave it upon arriving in a new city in exactly the same way.
- No labor-intensive work filling the area — just a small forest on both sides of the road and a distant static background, like mountains. The road length is 5 minutes of real-time driving. That is, the player manages to feel that the drive is happening, manages to drive the car, but doesn’t get tired of it (plus, as always, there’s a teleportation button available).
- The main part starts here: roughly in the middle of the road there’s a roadside rest area with a diner. Actually, that’s why you’d go there. It could have an interesting interior and a selection of snacks unlike any found in the cities, plus a shop with unique souvenirs (unusual figurines; special bait for fish found only there, etc.). Ideally — a small motel where you can spend the night, and, for example, a large lake shore adjacent to it where you can fish. Naturally, with its own unique fish species to add to your collection, and perhaps with a chance to find something on the bottom when diving. The lake is freshwater, of course, we’re not talking about working out the bottom the same way as in Cahaya.
- Children there can run around in nature (see a fox or raccoon, yes!) and swim, play on a playground at the diner. If you place a bowling alley there — that’s a wonderful activity for the whole family.
- As a result — you can go there even just “for the weekend” with the whole family, then return to the same city rather than continue to another. And car driving gains additional purpose, because right now within the city there’s no real need to drive — it’s much faster to get everywhere by public transport.
BY TRAIN
- Exactly the same loading of a separate location. The family boards a car roughly the same way as settling into an ordinary house, the only difference being that it’s constantly moving. This is where that very Paralives mode with its character creation would fit well.
- On the train the journey continues endlessly, until the player gets bored, without stops. Day changes to night and back. During the journey we can walk through the cars (you don’t need many, one or two sleeping cars are enough), where NPCs are also traveling, and actively meet them, communicate, make friends… In short, all the same as in the game, just in limited space. For very wealthy sims, you could allocate a luxury car at the end of the train so they travel not in an ordinary compartment but in comfort and separately from others — with a private dining car, lounge, television, a bed along the window and everything else that’s appropriate in such cases.
- On the train there are conductors who can take orders for food and drinks, and they would bring it right to the compartment. In the “luxury” they also do cleaning — wash dishes, vacuum, take out trash…
- Naturally, there’s also a dining car where you can go eat in a more atmospheric setting.
- Past the windows, forests and fields, lake shores cycle past, sometimes the train crosses rivers on a bridge. All this — in a closed loop: the camera is tied to the train and doesn’t fly far from it, so there’s no need to build a huge location that the train would physically drive on while the player could try to “travel the camera separately across the map”.
- When the player gets tired of the journey — they click the completion button, and the family goes to the final city through a loading screen.
And it doesn’t matter that the cities are territorially on different continents, and of course, in reality you can only get there by planes. In this case you can disregard that, and drive there by land just the same, and leave planes specifically for instant travel. Making them a separate game zone would seem boring to me (too little space), but overall if desired you could implement similar game mechanics in them as in trains, only it would be some kind of double-decker aircraft with business and first class, and endless flight, with clouds drifting below. Though I think all players would only fly in the “luxury”, and on the train in a regular compartment there would be something to do, chatting with neighbors 
Such are my suggestions. It seems to me this would greatly diversify the game, adding emotion to the travel process. There’s a Russian saying “The theater begins at the coat check”, implying that a person begins to enjoy a visit to a cultural venue from the moment they hand in their coat at the checkroom and find themselves in the foyer, where they can chat with their companions in anticipation of the show, go to the buffet, buy a theater program, rent binoculars, go into the hall and sit there, admiring the interior. And it’s important that this entire preparatory procedure be pleasant: polite staff at the coat check, tasty food at the buffet, pleasant conversation partners, beautiful interior… And the show itself is already like a final chord, the finishing touch. Yes, the most important, but the prelude to it can make a visit truly unforgettable (or spoil everything to the contrary).
So a journey before arriving in another city could add additional charm to the whole trip. Thank you for your attention to this idea! 
