A race-day brief should collect the current organiser's instructions in one usable plan. Check the race edition and publication date before using a map, elevation profile or start schedule. An old article about a famous marathon is not evidence that next year's route is unchanged.
Start with the organiser
For London, use London Marathon Events for its training resources and current event information. Keep ballot or entry decisions separate from training assumptions; an ambition to enter does not establish a confirmed place.
For Boston, begin with the Boston Athletic Association's marathon pages, which link athlete, spectator, qualification and results information. For Paris and New York, use the current official event site and entrant communications to obtain the relevant year's route and guide. This page does not claim an independently verified elevation total or official partnership with any event.
Turn the course into decisions
Mark the start access, significant course sections, available facilities and the finish exit. If you use an elevation profile, confirm its source and scale. GPS elevation can differ between recordings; a single number does not describe where the demanding sections occur.
For a hilly course, discuss preparation and effort with the plan's author or coach. Do not apply a precise split schedule copied from an unrelated route. Check whether congestion, bridges, turns or start arrangements affect how practical a target will be.
Prepare separate runner and spectator plans
The runner needs entry documents, arrival instructions, kit rules and the route to the start. Supporters need permitted viewing points, transport and a meeting place after the finish. Choose a fallback meeting point and contact method before the day.
Use official timing for results. A spectator map may help supporters understand progress, but a delayed location or ETA should not override closures, marshals or the agreed meeting plan.
Check again near the event
Save the latest official guide and note what changed. Share one current version of your own brief with the group. Weather, access and event instructions can change after a training plan has been written.
Runwiv is in pre-launch. Its event-tracking overview describes the intended workflow, not a guarantee of access for your race. For a local first parkrun, use the separate first-visit checklist, since its participation process differs from a mass-entry marathon.