Replacement for Longfellow

I have Longfellow scheduled for next weekend, but I’m not sure that I’m going to be able to fit it in, unless I :

a) wake up at 2:45am (not keen on that)
b) break it in two - maybe 2.5hrs + 1.5hrs - with a 5km parkrun in the middle. (It’s kind of expected that I attend parkrun as the rest of the family is there).
c) Go shorter, but go harder.

What do you suggest would be best?

c)

I nearly went insane doing Longfellow last week on a spin bike (bad weather or I would have ridden road bike). Other than mental conditioning, I would say “C” would give more bang for the buck.