Robust August

[Sweder]

The best laid plans ... or not. More like the curse of the working classes.
All too familiar mate. Missing three long runs in March cost me dear in the Brighton marathon this year. You're right to focus on getting the long ones done, just don't get too hung up on running the four hours. I don't know too many who've done that in training for a 26.2; 3, 3.30 seems plenty long enough to get into 'wall' territory.

Besides, as you point out yourself, running whilst knackered is like running the last hour or so of a long run. I reckon you'll have got more out of that than you might think.