It's going to be a case of diminishing returns. He needs ~6,700 yards. The most likely scenario is that he starts to decrease in yards every year until he retires. The trend could follow something like this:
- 1600 yards (31 yrs old)
- 1300 yards (32 yrs old)
- 1100 yards (33 yrs old)
- 700 yards (34 yrs old, injury)
- 800 yards (35 yrs old, being crazy generous)
- 400 yards (36 yrs old)
- 300 yards (37 yrs old)
And this would land him still 500 yards short. RBs over 30 get injured more often and remain sidelined for longer. In this projection I assumed he didn't get injured/miss games for 3 years which is highly unlikely. And giving him generous amounts of yards he still fell 500 yards short. At some point a younger back will be performing better and he'll be shipped off probably to be a backup, or if he's lucky to act like Gore and assist what should be a contender. He seemed to be slowing down at the end of last season, so I don't see him having 6-7 more seasons in him, and that's what I think it would take for him to reach the record.