Alright, well 50k is like 30 miles, and if you run ~6mph it's going to take you around 5hrs to compleat.
That's if you keep that pace the whole time.
But since you plan to walk some of the way which is about 3mph it's will take you ~10 hours.
So I guess you know what you're up to today.
Geez... You can be away from home for 10 hours but you can't go get a cup of coffee with me haha.