Charities are lining up activities in preparation for the event on 17 April.
Action for Kids has drafted in Amazon to undertake national media relations, as well as manage partnerships with corporate sponsors.
The agency has lined up famed fundraiser Lloyd Scott to complete the course facedown in a nine-foot long costume of Brian the Snail, one of the characters in the 1970s TV series The Magic Roundabout, accompanied by other characters from the show.
But Diabetes UK head of comms Paul McDonald said his charity's PR strategy would take a different route - he plans to send out a large number of local emotive stories that can be syndicated across the charity's social media pages to promote its key messages.
Forster director Peter Gilheany suggested the 'quirky' running costumes route had turned into an 'arms race', advising charities instead to use human interest stories and celebrity runners.
He said: 'The key these days is to make sure you extend the reach of these stories through social media and give people a chance to immerse themselves in the preparation. This is likely to help increase fundraising, which is what it is all about.'