12,000 Yds rushing is the benchmark now. Every Rb who has surpassed that mark except Frank Gore is in the
HOF. Gore will make it once he's eligible. I doubt the HOF voters would make a satellite back exception
for Kamara or Christian McCaffrey who has nearly the same numbers as Kamara.
Fwiw, Fred Taylor has 11,695 career Yds,and Steven Jackson has 11,438 and I doubt either of those
two will ever make it.Same with Corey Dillon with 11,421.
https://www.pro-football-reference.com/leaders/rush_yds_career.htm
edit- Adrian Peterson isn't in either,but like Gore he will be a lock