The portal into the expansion isn't going to lead immediately to a queue. With the space available it'll likely be a mini land like DK but smaller. There was a mock-up posted a few pages ago showing how the layout of the space fits in.
See above—they'd reroute the current service road around SNW's expansion. The new road would connect to SNW and the new land whenever they add a new portal/world to Epic.
In the photo below you can see a smaller service road behind DK is already in place. If and when the SNW expansion is built and the service road is rerouted it won't impede on the access needed for existing maintance. There might be some slight modifications in the area closest to the DK doorway if I had to guess though nothing substantial.
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I don't know about you but I'm starting to think Universal planned ahead somewhat.