actual the andals remind me of the late bronze/early iron age indogermanic migrations, as these guys also brought iron working with them. so you should definetely seek out stuff among the antiquity or at least the dark age mods. oc, the andals already seem semi-motheistic and the concept is chivalry is noted, but given the timeframe, it wouldnt be as defined as the faith and knighthood in 300 AL (they brought the "
warrior tradition of the
knight.").
the mods description so far mixes up the timeframes imo, so perhaps you should choose either an
andal invasion, andal expansion or a
warring andals approach.
an andal invasion would play out "
between 6 thousand and 4 thousands year before Aegon's Landing". "
The Fingers were the place where the Andals first landed, to wrest from the First Men the place that is known today as the Vale[3], in successive waves they spread. The wars between the First Men and the Andals lasted hundreds of years,"
we dont know much about the intial phase, any wars would already be ongoing, and the andals more widespread than the vale for balance purposes.
we know few of the leaders, one would be Ser
Artys Arryn . as he drove the last first men from the vale, he could be part of the
andal expansion.
giving grrms timeframe (
"They created great kingdoms of their own, but this process was somewhat slow, they expanded to the Iron Islands roughly two thousand years after their initial invasion.") a mod including the mudds should play out some centuries after the initial invasion ("Eventually, with Andal kings joining forces and extinguishing of
House Mudd (the house of the
River and the Hills kingdom of the First Men), the Andals were able to invade the
North."), and the ironborn would still be unconquered. Dorne is described as "
a confederation of bickering, feuding states.[4]" problematic here is that there were many petty andal kingdoms, about which we know hardly anything.
ie the hightowers were allied to the andals, though we dont know if they bowed to the first men gardeners or the andal gardeners.
as the gardners were founded by a mythical first man and continue to rule til AL, this is either a continuity error on grrms part or an indication that the reach was taken over by andals who continued the gardener line, perhaps by marriage orotherwise peaceful.
the warrings andals is probably easier, as there is much more information, like your list kings. the known kingdoms are established already, with the known ruling houses.
we dont know much about the riverlands though, only some houses of kings and that they were conquered first by the stormkings and then the ironborn. aparently, "
The last native king was killed by Stormland invaders about 360 years before Aegon's Landing."
Harwyn Hardhand took the riverlands from
Arrec the Storm King. being the grandfather of harren, thats probably a bit close to the targaryen invasion.
its said that under
Qhored Hoare the ironmen reached the peak of their expansion, though they lost much of that afterwards and the riverlands were taken much later: "
Under King Qhored Hoare the realm of the ironborn reached the peak of its expansion, and it was said that all the western coast of Westeros where the salt of the sea could be smelled or heard the crashing of waves were under their control. Although it is unlikely that this assertion is literal, since with all probability places like Oldtown or Lannisport have never been ruled from the Iron Islands, it is still remarkable that the ironborn could hold places as distant as the Arbor. ".
interesting for the riverlands are bracken and blackwood, though information is contradicing, they were either kings during the age of heros and bowed to the
King of the Rivers and the Hills, (not to be confused with the andal
Kingdom of the River) or their status ended when the andals came.
hope that helps in defining it a bit more.