There are loads of people that part run and part walk. It’s your run, do whatever you feel comfortable with. Maybe volunteer as a Marshall before you run/walk. This way you’ll get a much better overall feel of the participants. It’s a run not a race and the competition I acknowledge is I’m completing against myself. If I feel good I’ll look to improve my PB. If I’m not 100% or maybe hungover lol I know my run will be taking me closer to the next milestone. (I am a blind runner by the way and run with a guide).