The question you need to ask your self is can you produce 3.3 dogs per minute, every minute for 10 hrs straight?
And 8.3 per minute on Saturday?
You need to know what your max output per hr or day is and figure on that.
Yes you will have the opportunity to sell a lot of dogs, but I think 7000 is an unrealistic number for one hot dog cart.
Where would you store 140 cases of dogs?… That takes a lot of room. You would need mechanical refrigeration.
How are you going to store 400 18 packs of buns out of the sun, weather, off the ground, you can’t stack them more than 2 deep or they will be crushed.
I have a problem storing a few hundred buns and rolls for an event and I have a 20′ trailer.
Then there is the problem with the “estimate” of attendees, promoters ALWAYS pump up the numbers. Search on here about that…plenty of threads on attendance.