Noone has mentioned the fan run conventions, particularly Shore Leave. That seems to grow every year, and lasts for most of a week. There are so many things to do there that people don't sleep for days.
The fan conventions are less likely to feature celebrity actors, and more likely to have writers and other folk. Plus fan-made episodes, workshops of all sorts.
Unless I am cycling in France, I will be there next year.
Plus there are regional gatherings of Starfleet International, and probably the International Federation of Trekkers.
All these events have a decidedly different feel from the commercial ones where latinum is king.