Can't stop thinking about this so here's what I think. Roanoke
Annesburg and Van Horn would mostly be abandoned. The game hints at the new railroad not going away from these towns. People would realize how bad Annesburg is after the area gets so polluted and people would leave in floods. Felons would still hide out in Van Horn. The town is in an even worse condition then what it was in 1899. The area would be extremely polluted and the environment would be devastated. A few years after the events of RDR2, a new town would be built north of the main area of Roanoke and be the main city of the region. Many environmentalists hope to turn the region around and restore its beauty. But, many think the region will never be restored and the ever changing world has left the region behind.
Butcher Creek would still be home to people wanting to get away from modern civilization and wanting to keep their way of life. Time has not been kind to the people of Roanoke. Many people would go missing in Roanoke and never be found again. No one would really visit Roanoke, it’s an area many avoid. Except for the ghost hunters, treasure hunters and teens looking to screw around. This is the perfect place to commit a crime. The region north of Annesburg would be somewhat untouched by the pollution but Dragic’s lab would be a popular place for tourists. Its out of the way but a trap for people to spend a little bit of money.
Fort Brennand would become a historical site, full of people wanting to find Civil War relicts. The fort would be rebuilt but not in it's original form.
The Bayou area
•Saint Denis would become massive, taking over more than half the space in the Bayou and taking over areas on the other side of the river. The mob would still rule the city and the city would be plagued with crime. I think the city would eventually flood from a hurricane (think of Katrina in 2005)
Sisika would be shut down probably due to corruption and would become a historical site similar to Alcatraz.
A ton of the Bayou animals would be killed off and the undeveloped areas would probably become a national park or a wildlife refuge. Lagras would still be around, albeit not many people would visit.
Scarlett Meadows
It’s my personal headcanon that the raiders were destroyed sometime in chapter 4 and moved to Texas. Shady Belle would either be another historical site or an elite would rebuild it.
The town of Pleasance most definitely would be destroyed to cover up the past.
The last of the Grays would go bankrupt and probably lose the mansion which would become a historical site. T
he ruins of Braithwate manor would become a town eventually. The land around it would be small farms.
Bolger Glade would most definitely be a historical site.
Rhodes would still be very racist which would be typical for a southern town, especially in the 60’s. Rhodes would still be small town. Clemens Point would most definitely be a real estate spot along with those islands
Ambarino and The Heartlands
Colter would be a ski town and Lake Isabella in the summer would be popular. But the rest of the western grizzlies would be isolated and not very visited. Eastern Grizzlies would be a very isolated area
Let’s pretend that the capital is north of the map. It would essentially be a city similar to Helena MT
The Wapiti would eventually be allowed to return to the reservation. The reservation remains poor and isolated but the natives can live in peace
Cumberland Forest would either be cut down. Or merge with the grizzlies and Fort Wallace would be abandoned and be a historical site
Emerald Ranch would destroy all the small farms in the area and be the main ranch in New Hanover. It would also grow so it can feed all of the region and become massive. The family that owns it would become extremely rich
Cornwall Oil Fields would now be wind farm and solar array with a Native American memorial.
The Heartland’s plains would go from a green color to a yellow color
Twin Stack Pass would be a historical site. Horseshoe Overlook would probably just become a homestead.
Valentine would be similar to Cheyenne Wy or Witchita Kansas where it's history really affected it. It’s history would loom over it. Valentine wouldn't be a big city but big enough.
Many animals in the Heartlands would go on the brink of extinction but would make a come back. Bison would become a protected species. The Dakota River would be a much larger river and more mighty.
West Elizabeth
Strawberry would be much bigger and more modern. Would become an ultra elite town, think of Big Sky Montana or the Teton area.
Fort Riggs would be a historical area but a very somber area still. A big portion of Big Valley would be a national park. Hanging Dog would be a part of the park. Either Geddes loses Pronghorn and it becomes a historical site or he keeps it. The area protects a ton of animals.
Cochinay would become a ghost town and a historical site. Some of Tall Trees would be cut a few years after RDR1 but almost all of it would eventually grow back. The area would become a national park Manzanita would become a small town still trying to retain it’s western feel. The Natives from RDR1 would create a settlement and a new reservation would be made.
Blackwater greatly expands taking Thieves Landing and the Railroad camp The wreck of the Serendipity would be a historical site.
No way Jack keeps Beecher's Hope, maybe becomes a landmark or just gets eaten up by Blackwater.
New Austin
Pikes Basin, Stillwater Creek and the area north of Pikes Basin would become a national park/public land. Bison would inhabit the plains in Hennigan’s Stead and be a protected species.
Manteca Falls is a popular tourist spot but also a border crossing.
Macfarlane’s Ranch loses a lot of land which becomes a town. Small ranches and farms dot the landscape. The main ranch would keep the house and the area north of it.
New Austin would have so many problems with Immigration, drugs and crime.
Armadillo would expand into Twin Rocks and to the area near Coots Chapel. Armadillo becomes massive because of the oil companies in Rio Bravo with Armadillo's wild west past being similar to Valentine but much bigger
Lake Don Julio, Riley’s Charge, Fort Mercer and Rio Del Lobo become a national park.
Ridgewood takes over the farms and ranches in the region including Rathskeller Fork.
Plainview would be a massive oil rich area and the border crossing at Ramita de la Baya would be a crowded area with a new albeit small town being built here. Benedict Point would eventually be abandoned
Cartel violence and criminal conflict would be rampant at the border
A national park is made in Gaptooth because of the Joshua Trees. Tumbleweed is still a ghost town and popular with photographers
A new city is built in The Sea of Coronado