Foster blows Campbell away when you consider that he ran 2:11 to get a silver medal in a major championship at age 44 (Commonwealth Games-back when they meant something), only three minutes off the WR, and that he was a major contender in every world-class mnarathon he ran in the early 70's. Campbell comes along 20 years later and shaves the record by seconds in Boston with a tailwind. No comparison.
Other notables: Ed Whitlock 2:52 at age 69 and 38:09 at 70, Derek Turnbull regularly running 16/34 minutes in his 60's (must be the NZ air- those Kiwis have records all over the Masters distance charts!).
And Yekaterina Podkopayeva w/ 3:59 at age 42 may take the cake, but I always must suspect those ex-Sovietski performances, unfortunately.
Overall Payton takes it though, WR's all through his 60's and 70's- his 14.35 at 80 is even better than his 200!