I proposed this idea not too long ago (but importantly, before Paralives came out, so it’s not taken from there) — introducing a travel system between cities by train or car. Nothing massive in scale, no permanently operating stations or airports, and definitely no customs checks, border controls, and all that! But now I want to present this as a separate suggestion with more details.
Here’s how I see it being interesting:
BY CAR
- A separate location is created for car travel in the form of a long, narrow highway. Players enter it through a brief loading screen and leave it upon arriving in a new city the same way, through another loading screen.
- No labor-intensive large-scale decoration — just a small forest on both sides of the road and a distant static background, like mountains. The highway length is 5 minutes of real-time driving. So the player gets to feel that the journey is happening, gets to steer the car, but doesn’t get tired of it (plus, as always, there’s a teleportation button available).
- Here’s where it gets interesting: roughly in the middle of the road, there’s a rest stop with a roadside café. Basically, that’s why you’d drive there in the first place. It could have some interesting interior design and a selection of snacks unlike anything you’d find 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 right next to it where you can fish. Of course, with its own unique fish species to add to your collection, and possibly a chance to find something at the bottom when diving. The lake is freshwater, naturally — we’re not talking about developing the bottom the way it’s done in Cahaya.
- Kids can run around outdoors there (see a fox or raccoon, yeah!) and swim, play at the playground near the café. If you set up a bowling alley there — that’s a wonderful activity for the whole family.
- As a result — you can drive there just for a “weekend” with the whole family, then return to the same city instead of continuing to another one. And driving a car 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 separate location loading. The family boards a train car roughly the same way they move into a regular house, the only difference being that it continuously moves. This is actually where that Paralives character creation mode would work well as an analogy.
- The train journey continues endlessly while the player is interested, with no stops. Day turns to night and back again. During the journey we can walk through the cars (you don’t need many, just one or two sleeping cars is enough), where NPCs are also traveling, and actively meet them, chat, make friends… In other words, everything that’s 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 a regular compartment, but in comfort and separately from others — with a private dining room, lounge, TV, a bed along the window, and everything else that comes with such cases.
- The train has conductors who can take orders for food and drinks, and they’d bring it right to your compartment. In the “luxury” section they’d also do cleaning — wash dishes, vacuum, take out the trash…
- Naturally, there’s also a dining car where you can go eat in a more atmospheric setting.
- Through the windows, forests and fields pass in a closed loop, lake shores, sometimes the train crosses rivers over bridges. All of this is 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 where the train would physically travel and the player could try to separately “travel the camera around the map”.
- When the player gets tired of the journey — they click the completion button, and the family travels through a loading screen to the destination city.
And it doesn’t matter that the cities are territorially on different continents, and realistically you could only get there by planes. In this case you can disregard that, and travel there by land in the same way, while planes remain for instant travel. Making them a separate game zone would be boring, I think (too little space), but overall if desired you could implement similar gameplay mechanics in them as in trains, just with some kind of double-decker plane with business and first class, and endless flight with clouds drifting below. Though I think all players would fly only in the “luxury” section, whereas in the train and regular compartment there’d be things to do, chatting with neighbors 
That’s my suggestions. I think this would greatly diversify the game, adding emotion to the travel experience. There’s a Russian saying “The theater begins with the cloakroom,” meaning that a person starts enjoying a visit to a cultural venue the moment they hand in their coat and find themselves in the foyer, where they can chat with companions in anticipation of the show, visit the buffet, buy a theater program, get binoculars, enter the hall and sit there admiring the interior. And it’s important that the whole preparation procedure is pleasant: polite cloakroom staff, delicious food at the buffet, pleasant conversation partners, beautiful interior… And the show itself is then like the final chord, the finishing touch. Yes, it’s the most important part, but the prelude to it can make a visit truly unforgettable (or ruin it all).
So a trip before arriving in another city could give the whole journey additional charm. Thank you for paying attention to this idea! 
Just an illustration so you can see it visually. You’ll definitely do much better! 
