Carbohydrate Loading : Australian Institute of Sport : Australian Sports Commission
^^ i have used that protocol for 5hr+ mountain bike races and tbh as someone who was/is doing 10-14hrs of cycling per week i don't really see the value in it. basically, i think there's more to be gained through persistent training and efficient post-workout restoration of glycogen combined with some long term improvements in fat adaptation/efficiency.
Top 10 Biggest Mistakes Endurance Athletes Make
^^this info makes a lot more sense to me for longer events.
otoh, if you're purely a HIIT, xfit or resistance trainer and not depleting/restoring muscle glycogen multiple times per week then maybe there is something in it for you.
biggest mistakes i have seen (and made) with carbo loading is just massively over-eating carbs/dietary fibre that simply cannot be stored as glycogen and then hitting an event 2-3kg overweight because you're retaining water and your gut is all backed up...
how long will tough mudder take, anyway? is it actually long enough to seriously deplete muscle glycogen?