You have done the long runs. The last three weeks are about arriving at the start line fresh, not fitter. Cut volume, keep intensity, and trust the work you have already done.
Week three: cut volume by a quarter
Keep your usual run days but shorten each one. Your last 30 km long run should be behind you. Keep one session at goal marathon pace.
Week two: cut by half
Most runners feel sluggish here. That is normal — your legs are repairing. Keep a few short strides at the end of easy runs so they stay sharp.
Race week: stay loose
Two or three short runs, one with a few minutes at race pace, and plenty of sleep. Nothing new: no new shoes, no new gels, no new breakfast.
