The correct answer to this open question is the following.
My plan of activities would be the following.
The first thing would be the executive summary of the plan.
Then, the objective and goals of the event. I would follow with the permissions with the locality, policeman, and transit authority.
Regarding operations, I would elaborate a list of administrative support, registration process, judges, electronic watches and markers providers, and medals or trophies.
I have to prepare a budget to get ready for the financial situation. The price of the ticket per participant is very important.
Regarding marketing and promotions, I would invite some sponsors and I would present to them the sponsorship manual so they can choose what fits them better.
Regarding PR, I would use social media but some traditional outlets such as radio interviews and some printing media advertising.