If Yeovil can beat Forest, we can beat Watford. As you say it's almost inevitable. And the fact that nothing is inevitable in this division is the only thing that is inevitable.
I missed the Leeds game first year at the Amex because of the Balcombe tunnel collapse. It was on Sky and I was convinced many others would miss it but it was the biggest crowd of the season at that point. People will find a way to get there. Most other services will be running pre-match as well.