The changes I intend to enact:
(1) one or two partner clans for each invading team. I have some ideas for who works with who, mostly things to minimize strife between cooperating clans.
(2) Different Wolf Leadership, who overthrew Ulric for trying to act as a brake on the invasion. they pay homage to the goal of terra, but they are more interested in recovering worlds of the inner sphere, liberating them from the successor states. There will also be some alterations to other clan leaderships.
(3) as Eric Icaza pointed out, having it be a migration as much as an invasion, and making their forces much larger and thus a legitimate threat to the whole of the sphere.
(4) Periphery Logistical Bases, both acting as localized maunfacturing, training and depot worlds, as well as rallying points for the migration following after. Additionally, a foreward capital world for the clans will be established, allowing the clans to hold council while in the field.
(5) Reactivation of cached material, sohlama warriors and having some clans introduce second-round Trials of Position, allowing would-be warriors to test into outdated mechs, vehicles, infantry units, to help defend liberated territory. For Clan Wolf, I have reactivated marauders that are rebuilt to resemble Timberwolf A and D configurations, a poor man's Catapult based Timberwolf Prime, a Charger rigged up to be similar to a Gargoyle Prime along with the addition of elemental carrying capacity. Reactivated mothballed Woodsmen that they found somewhere. a Longbow built into a budget Naga. For the Ghost Bears, its been Bombardier -> Mad Dog, and Banshee -> Executioner
Looking for suggestions for building other mechs into look-alikes for the other clans.
(6) One way or another, the clans after the first wave or two, realize that the inner sphere has no idea what they consider honorable combat, and rather than continuing to get enraged when they just fight barbarically, they start including a short introduction on clan combat along with their batchalls, and give the planet being conquered a choice, that they can conduct themselves honorably, or they can face the full might of the clan forces available.
(7) Turn down Comstar's offer of administrating the Occupation Zones. We do not need them to operate HPGs, and we have no reason to trust comstar like that. They ARE after all the organization who found us.
I do rather like your suggestion, Arkansas Warrior, of starting at the core, but that would be a logistics nightmare, I think.