Just looking at Pukkelpop. They shared 15* names with Sziget last year and made their main announcements at end of Jan/beginning of Feb. If they do the same this year, it might give us some strong ideas about who will be in announcement two.
*Fred Again.., Stormzy. Fontaines DC, Artemas, Blondshell, Sam Smith, Goldband, Skrillex, Raye, Grandson, Barry Can't Swim, Marc Rebillet, Crystal Fighters, Dead Poet Society, Becky Hill.
There is a traditional 9am "Thursday 5k" run that for the past few years i've semi-organised.
It starts in the Green Futures field, goes up to the park then does a sight seeing loop of the festival site. We usual have a couple of hundred like minded souls turn up. (and because it starts at 9 you have a chance of getting a shower afterwards)
It will be promoted on social media (and here) in the weeks leading up to the festival. Just keep an eye out for posts and turn up at 9 on the Thursday, make friends with fellow runners (organise meet ups on other days) and if you want to "Double-Bubble" with the slightly later and very slickly organised ravers2runners event.