WI: Larger Vinland

Have been giving this some thought - looked up my old TL posted on AHcom back in 2008 rewritten by 2020 with new information on American cultures and mostly DNA like referred in the previous post:

At this time ca. 1000 AD the Mississippian Culture is growing with larger polities from the major river and its tributaries river valleys. The Ohio River culture is developing.
There is a tradenetword between Mexican Maya and other cultures and the Caribbean and Gulf Coast of the Mississipian Culture so much probability of smallpox hitting the Valleys going down these to the Mississippi and into the Caribbean - Mexico cultures area possibly even going south with South American traders.

Found this Wiki entry of American cultures and if just reasonably correct it seems there is a highway to South America from the Valley cultures of the North America though probably the Norse will have to proceed from New Foundland to the Maritimes to really spread their paveway package!

Lets think of a year or two before the Norse realize what havoc they have been wrecking on the Natives in the new World; then they claim land in the Maritimes and Northern New England only refuelling the epidemics.
Along the way some livestock among these horses will go feral and put its own mark upon the America's.

The horses will go for the Midwest steppe while cattle will stay in the Eastern Forest's. Goats, Sheep and Pigs will go their own ways with the Pigs staying in the woodlands along the Cattle.

Word of the rich lands ripe for the picking will spread back to Scandinavia but building ship is a costly endeavour hence why the Norse going to the West was a Nobility trait - they had the funds to do so.
However by ca. 1300 the influx will come lessen and end around 1349 when the Plague hits Europe - Norway was particular hard hit. Then comes the worsening climate which will barr the voyages of the North Atlantic untill around 1650-1700. The Danish Pothorst - Pining Expedition may have sighted Labrador by 1472-73 and then turned home. Twenty years later a Spanish expedition lead by an Italian will reach the Caribbean.

This leave some 450-500 years for the Norse to increase and the Native Americans of both Continents to get back on their feet. The Scandinavians took 200 years to rebound from 536-40 Fimbul Winter to go a Viking.

Here the Native Americans have begotten a new agricultural package or at least part of it; Plains Indians on horses won't be impossible but so too will sailing ships Viking Knarr style as well as metals for real - arms, armour and all sorts of implements. Made of bronze, iron and steel. The wheel!

I have no idea how hard the European germs package will hit the Native Americans though of course the density of settlement will be a determine - the more peoples the larger the die-off. However with the OP assessment of Viking population growth the Norse will stay the few, in areas ruling the many and a mix of groups will happen if only to augment the hands to run farms and furnace as well as spin sails and chop down trees to build ships.

I expect those survivors of Native Americans to do as in Scandinavia post Fimbul Winter - landholding on fewer hands then prior. Also some religious upheaval is possible if the epidemic is swift and unforgiven. The more mentally overwhelming the more possible of some religious fall-out. In Scandinavia the God Odin of the aristocracy became the major god post Fimbul Winter.

The OP figures for Norse pop growth are wildly optimistic - with a window of 450 years before the Europeans appear they would have accumulated to 314,5 mio. peoples. The Scandinavians never accumulated such numbers.
The 1970's numbers of World population doubling was some 27 years.
If we go by a doubling every 30 years that will still make for almost 10 mio. Norse descendants in 450 years. Sweden today is some 10,5 mio so still optimistic I think as there will be some rebound of epidemics hitting back when mutations have taken place in the Natives. As we have seen it won't be as deadly as the original outbreak and Scandinavians are quite germ resistant beings but still some effect would be felt.

So far i know is classical historian Doctrin:
That Vikings abandon their North American settlement, because the locals were very aggressive to Vikings.
it could be Vikings inflicted that on themselves, by raiding Locals settlement...

Now put smallpox into this scenario, make it a Game changer !
For those who not understand, smallpox, was a very infectious disease, with fatality rate of 96% !
it took to 1970s until WHO eradicated smallpox world wide.

Back to topic
Imagine one of first vikings in North American settlement, carry the Smallpox virus and infects the locals !
and with no immunity vs Smallpox, the fatality rate will be near 99% under Native Americans.
The Viking suddenly have vast area for them self to Settle.

This same Mechanismen that happen as Spanish and English and French settle in America 500 years later.
Who brought Smallpox, chickenpox, measles to Native Americans, who died at millions, even before the coloniser arrived in their capital!

Here in this senario happen that at Viking Era around 1000 AD.
If others Europeans nations start colonising America in 16th century.
They face a serious problem: immunise descendant Native, who repopulated their lands.
and if Native learned from Viking how to make Metal, they better equip to fight the coloniser !

a very good book on that Topic is:
Guns, Germs, and Steel: The Fates of Human Societies
by Jared Mason Diamond
ISBN 0-393-03891-2

Gurps Alternate Earths II suggested: If the Vikings had discovered the fish of the Great Banks, that'd have helped a lot.

I haven't read Collapse but the trashheaps on Greenland have yielded fish and seal bones. Even if the Norse did continue with their agricultural package - going to such lengths as to make irrigation to be able to harvest hay for winter fodder and to keep on making Skyr they did adapt to surroundings to some extend. As these Norse were of North Atlantic stock they would rely quite some on what the sea had to offer. Just have a look at Iceland, Norway and Faeroe Is. today - their diet is quite different from Denmarks.

Then why didn't they make more use of fish - lack of timbers to dry stock-fish?! Without being able to use the timbers of NA in the quantity they would have needed liked I think that could be a possible.