The way they did it for Pandora on opening day was a queue to get in a queue to wait to get in the land. Took me close to 2 hours to get from the front gate into the land and I was in the park when the gates opened at 8am... the problem was it was an Early EMH day, so before the park even opened to regular guests, the land was at capacity and lines had formed to enter.
It goes without saying that Galaxy's Edge will be far worse and likely require a ticket system. I'm frankly not sure if they ever did that for Pandora but I think they will need to here.
I do know that for quite awhile, the only way into SWGE is going to be through the Grand Avenue entrance and Toy Story will be used as an exit only, similar to how they ran (and still run in busy times) Pandora where the only entrance is the main bridge and the only exit is the side bridge leading to Africa.