The trail boss says Matt better watch out for Strobo, who is "even bigger than you". Strobo was played by former boxer Buddy Baer, who was about the same height as James Arness, but considerably heavier. Buddy was the brother of heavyweight champion Max Baer, and once knocked Joe Louis out of the ring during a fight.
A young cowhand says the men Matt are looking for have gone west along the Ar -KAN-sas. This is not a mispronunciation, as the river flowing in that area is really said that way, and not as the state of Arkansas. Arkansas City is a town south of Wichita with a population of abut twelve thousand.
Buddy Baer then would be the uncle of Max Baer Jr., who played Jethro on the Beverly Hillbillies.