According to FedCom Civil War, p. 128, Hansen's Roughriders were pushed off Panpour by the Lexington Combat Group. No timestamp is given in this particular paragraph, but it is at the end of the Wave Four chapter (under "Other Actions" - Panpour - , p. 128) which is indicated to take place between November 3064 and May 3065. The deployment table on p. 184 confirms they retreated to Nunivak in a strategic movement where they sat out Wave Five (until January 3066). They aren't mentioned again afterwards.
MercSupp 1 repeats that they were driven off Panpour by the LCG and retreated to Nunivak, but offers no dates.
Next, it is stated the Taurians invaded and George Hasek hired the Roughriders. Unbeknownst to the Roughriders, the Bromhead massacre had happened already before the contract with Hasek was even signed, and the Roughriders learned of this en-route to Lindsay. (From Panpour, Nunivak is "north" while Lindsay is "southwest", so essentially opposite directions.)
MercSupp Update and Jihad Secrets: The Blake Documents (p. 81) both say the Bromhead massacre took place in 3067, with the latter source saying the Roughriders were on Panpour at the time.
Problem: The Roughriders had left Panpour on 23 February 3065 (FCCW, p. 128). And the Fighting Urukhai whom the Roughriders had mauled there left five days later, bound for Taurus, and became the catalyst that launched the Taurian invasion in the first place. The Taurians launched their invasion in 3067.
Should this be taken to mean the Roughriders moved to Nunivak first in 3065, were hired by George Hasek because of the Taurian invasion in January 3067, and moved to Lindsay via Panpour (a slight detour) so that they actually were on Panpour when the Bromhead massacre occurred?
(Do we have a date for the Bromhead massacre beyond the year 3067?)