With the cessation of eastward trade, Skrælingborg could no longer sustain as many artisans. A sizeable amount of the town left to build new farms, leading to the growth of Norðstaðr and the rebuilding of Miðrtunga. As relations with the native Abenaki were at their lowest point in history, new fortifications were erected in Miðrtunga and Eirsteinn.
Two new settlements were built further south, with Rasbeygja founded in 1414, and Miðrsunborg settled across the channel on Miðrsun in 1423.
The reconstruction of Miðrtunga.
Expansion of Norðstaðr.
Another impact of the isolation was reforestation. Demand had been high for timber in the Norse settlements on Greenland and Iceland, and as other settlements faltered, Skrælige was able to fulfill much of it. With that demand gone, forests were able to reclaim some of the land that had been clearcut before.
Expanded mining operations at Eirsteinn.
Finally, the lack of iron imports meant that copper mining and bronzeworking had to pick up the slack. Combined with a need for more metal for weaponry (see Continued Native Conflict below), the small mining operation in Eirsteinn had to grow. New machines were built to lift mined ore from the caverns, and more houses were built to accommodate the larger operation. Eirsteinn was now a town in its own right.
Another effect of the cutoff of trade was an escalating conflict with the Abenaki. The growing population had to spread out to be self sufficient, and this meant regular competition for hunting and fishing. After a poor growing season in 1453, Skræligens grew bolder in their incursions into the interior of the island. In late October of that year, the Abenaki fired arrows at one hunting party, injuring two and causing them to retreat. In earlier times the plentiful trade and integrated cultures might have calmed things down, but instead it just escalated tensions. Skræligen hunting parties began better arming themselves, firing back in minor skirmishes. It all came to a head on the night of the 2nd of November, when a small band of Skræligen militia went rogue and managed to sneak to the Abenaki village on Lake Asærban, launching a volley of flaming arrows and lighting the village on fire. The Abenaki who were on guard chased the militiamen and killed them, but it was too late. Several villagers were killed, and the majority of the village burned to the ground. This would become known as the Massacre of Abenakiborg.
The arson had not been approved by the Þing of Skrælige, and their first knowledge of the attack was the sight of fire and smoke upstream. The citizens of Skrælige prepared for a counterattack, but none came that night. Instead, the surviving Abenaki retreated inland, abandoning their village that had once been the centre of the larger tribe. For the next decades there would be no peace between Skræligens and Abenaki, with skirmishes continuing but no major battles.
The fort of Abenakiborg, built on the former Abenaki village.
After the massacre, the Þing did approve exploration and raiding on the mainland. Long distance merchants and fisherman had explored the area somewhat, but there had never been any need or desire to expand outside of the main island of Storreyn itself. Skrælige itself was more of an accidental settlement, too far from the Norse homeland to attract much immigration, but with enough resources and trade to easily support it. With reduced resources, no trade, and hostile Abenaki, the Þing decided that they should look back to their ancestors and explore, potentially raiding any native settlements they found on the mainland. This nostalgia for Viking raids did not end well for the Skræligens, however. The tribes on the mainland, many of which were also Abenaki, had already been warned of the Skræligens. The moment any of them began to set foot on the mainland, the natives immediately fired arrows at them. In most cases the Skræligens immediately retreated - the few times they did not led to bloodshed. By the 1470s mainland raids were stopped.
By 1500, Skrælige was somewhat stagnant. It wasn't struggling - apart from isolated incidents including the 1450s, food had been sufficient for everyone. However, it wasn't really prospering either, with an inability to expand off of the islands, and constant attention dedicated to the native conflict they had sparked.
As was tradition, another Manntal was commissioned in 1500, and the results were as follows:
Skrælingborg: 726 (-167)
Church & Market District: 243 (-5)
Miðrway & Docks (Formerly North & Docks): 387 (-130)
Outside of the walls: 69 (-32)
Vinstrileið village: 15 (-5)
Hœgrileið village: 12 (-5)
Nyrvænn: 225 (-7)
Main Village: 175 (-7)
North Village: 22 (-1)
South Village: 29 (+1)
Miðrtunga: 66 (+10)
Norðstaðr (Including one household outside the village): 78 (+62)
Eirsteinn: 77 (+57)
Abenakiborg (Formerly Main Abenaki Village): 9 (-87)
Smarvik: 41 (-17)
Rasbeygja: 25
Miðrsunborg: 17
Total population of 1264 (-12).
Big changes were to come, starting on the 29th of January, 1509, when a large ship of an unknown design was sighted on the horizon...
My impression from the Wikipedia "research" I did was that Norse explorers to the west were generally not very good at fighting natives. Iceland had no indigenous people pre-Norse settlement, Southern Greenland was uninhabited at the time, and some of the Sagas mention relations breaking down and the Norse being forced away in North America. Not quite living up to their mythology as fierce Viking warriors :) I figure with this and the amount of time that has passed so far, a stalemate with a bit of ebb and flow is the most likely outcome in armed conflict.