Longer than 12 miles.

Even if you had to carry the bike 12 miles through a mosquito infested mud swamp uphill.

12 miles can't qualify, regardless.

I agree that it's personal so my definition? an all day ride that goes fifty miles plus. Of course that depends a lot on the terrain.

At some point you should be absolutely in the middle of nowhere , so that riding back to the trailhead takes the 2nd half of the day. Whether it's a huge loop or a long out and back.

So riding all day at a resort does not qualify to me, nor does riding the same 15 mile loop all day.

Broken bodies and bike, bonking , getting lost and / or running out of water and daylight enhances the story, but is just a side effect of a good epic ride, it does not make a ride 'epic'.

but anyway........more pictures in this thread less BS