I may have missed some posts on this but this issue came up on my other recent thread re Texas Rangers.
The present house rule we are using:
Any raiding outside border states must be with a leader or within 2 regions of a leader (this is needed for Union invasions of CSA coastal areas, where sometimes the stack with the leader must split out from under the original leader).
I am thinking of further refinements with respect to Texas rangers:
--Texas rangers can only be used as raiders with no leader in SW states (Texas, Indian and Kansas territories, and off map Arizona box): outside of these areas they must have a leader, as well as other regular cavalry.
--Regular cavalry without leaders can only raid in border states if it is into states they originated in; e.g. only CSA cavalry raised in Kentucky can raid in Kentucky without a leader.
--Cavalry with a leader can raid anywhere.
Perhaps that sounds overly fussy, but cavalry ants running amok behind the lines blowing up everything they can find can have a huge effect on offensives. There were only a few Forrests and Morgan types actually able to do this. Re Texas rangers, historically, most of these ranger units were “mounted volunteers” used in Sibley’s brigade which set off for Arizona.
Actually I think there should be a "deep raider" icon to designate certain cavalry leaders on both sides as capable of going two states beyond the nearest controlled state, or something like that. Off the top of my head--CSA: Stuart, Forrest, Price, Morgan, Hampton, and U.S.: Grierson, Wilson.