Dogtrousers
Kilometre nibbler
Have someone standing by with a laptop figuring out how far you are down you virtual route. Then when you do want a toilet break they can check Google Streetview and say "no, there's no convenient bushes here. You'll have to carry on for a bit".Splitting it is a cop out... either do it proper or don't do it at all, solo, no breaks (other than for the toilet). Overcoming the "boredom" etc is the challenge! Remove/minimise the challenge and you remove/minimise the motivation for donation!
Good luck btw. That's quite a challenge.