Since Affirmed won in 1978 days rest between last 2yo start & 1st 3yo start.

Big Brown 183, I'll Have Another 152, Smarty Jones 41, Funny Cide 100, War Emblem 63, Charismatic 19, Real Quiet 34, Silver Charm 43, Sunday Silence 105, Alysheba 126, Pleasant Colony 98*, Spectacular Bid 87.

That's an average of 88 days (82 without I'll Have Another), a median of 93 days (87 without IHA) . Add a day if going days from one race to the next.

* I couldn't find Pleasant Colony's PPs, but I know he ran in the Remsen in 1980 & Fountain of Youth in 1981, 98 days rest.

Edit: The biggest problem with this thread is that because there have been no Triple Crown winners since the 1970s, you can't compare previous Triple Crown winners to present day horses. While the winners of the 1970s all took about 4 months off in the winter, they then raced with little spacing. Secretariat & Seattle Slew raced in the Wood, 2 weeks before the Derby. Affirmed took over 4 months off but then raced 4 times from his March return to the Derby, had one stretch of races 10 days apart & had 1 day short of 3 weeks before the Derby, racing on a Sunday 3 weeks before the Derby. It was a different era.