Suggestions on where to be to watch Tinker Bell fly from the Cinderella Castle to the roof of Tomorrowland Terrace.

Tinker Bell begins the Happily Ever After fireworks by "flying" from Cinderella Castle to the roof of the Tomorrowland Terrace, which is in the corner linking Main Street USA and Tomorrowland. So you can see her very well from the Tomorrowland Terrace Dessert Party (https://disneyworld.disney.go.com/dining/magic-kingdom/tomorrowland-terrace-fireworks-dessert-party/) or the cheaper Dessert Party with Plaza Garden Viewing (https://disneyworld.disney.go.com/dining/magic-kingdom/tomorrowland-terrace-fireworks-dessert-party-plaza-view/). The main difference between those two is that the former has seating along the rail of the restaurant while the latter is standing room in one of the garden areas nearby in the hub.

The Terrace party basically looks like Tink is coming straight at you, while the standing room she would go just to your right. If you don't want to do a dessert party at all, standing on the bridge from the hub to Tomorrowland is a good spot for Tinker Bell watching, although she would go over your head and away from you.