Do nomads travel the world? Their only modes of transportation appear to be land vehicles. Thelas Nation being the only exception (as far as I know, but I could be wrong) as they travel by water.
I think these wildly divergent paths and whether V's LI stays with them or leaves makes V's return as a protagonist for the sequel sadly unlikely. Usually, developers pick canon endings for sequels but with how different V's life ends up being in the endings, CDPR could simply decide it's better to just leave it be and give us a new protagonist.
Why would V from The Sun ending leave Night City and go somewhere else for example? Why would V from The Star ending suddenly go and spend most of their new adventure in yet another metropolis? As much I love V, the last thing I want is for CDPR to decide that the ending that's not happy at all for my V is now canon and that my street kid V who had more reasons to stay in NC than leave is now suddenly palling around with Panam in a desert.
As far as the Aldecaldos, yeah it seems they only have land vehicles, but they never mention they don't have water ones (not that I can remember). And they could also work out a deal with another clan or get their hands on some water vessels. But I guess I was thinking of them traveling the USA.
Anyway from what I've gathered in other forms and sites is people want there to be a canon ending. Granted we will have to see how the expansions go but right now I see two endings that can continue but one only that could really be canon. That one would be the Star ending. It's the only one that shows signs of hope. You get a good tarot card read ( when all the others are pretty dark), V mentions Vik's drug is working, you get the bird showing up on the car window, the swallow, which is a symbol for hope, and Panam says she has contacts that have helped others out of deep deep cesspits and they can help V. And your chosen romance follows you. As far as Star ending V going to another city, it's not out of the ordinary, nomads do go to other cities depending on if they need jobs or supplies. The Aldecaldos were in NC for that very reason, just depends on the clan. And gives a new city to explore in a sequel.
Whereas the other endings V dies or just accepts that he/she is going to die. The Sun ending being where V chose to be a legend instead of living. So if that's the case then yeah, your V wouldn't go to another city, he/she would stay in Night City until his/her final days, and that's how your Vs story would end if you choose to. As V says in that ending " Night City is my city, I still got something to prove".( And the Sun ending is the only ending some LI leave or stay.)
I imagine it's designed that way because in that ending V doesn't care about surviving, just one more fight to be a legend. And the name of the ending kinda fits "The Sun", fly to close to the sun, end up getting burned. When I think about it even Dex kinda mentions the two endings where V is still alive. Something like would rather die a ripe old age (Star ending) or go out in a blaze of glory never seeing your 30th (Sun ending).
I guess it will come down to the 2 expansions. Maybe one will be about the Crystal Palace where you can see and experience Vs final blaze of glory with your LI or at least the ones who stay and getting a happy ending although short because V is still dying. The one who leaves for good seems to be Judy if you choose the Sun ending. Panam leaves but says she will wait for you. And the other expansion is about saving Vs life for good and getting that type of happy ending and possibly more story's with V. It just comes down to is V willing to sacrifice his/her dream to have a chance at living.
Who knows, maybe there will be two ways to cure V in the expansions. One involving the Crystal Palace and the other involving the Aldecaldos. Both have possible different consequences for curing V. Still leaving both endings open to a sequel. And then there is Judy, who I think is going to play a huge part in saving V regardless of what ending you chose, Star or Sun ending. Since she dabbles in rewriting brain synapses I believe.