[emuzombie]

Step 1: Third round of Goldrush, 1 or 2 Engies build teleporter entrance, upgrades it to level three.

Step 2: Sneak behind enemy lines (or gets ubered to get there) Builds a sentry, dispenser by the final cap point.

Step 3: Build teleporter exit after first point is capped.

Step 4: Watch red struggle to get out of their base.

Step 5: ???

Step 6: Profit!

Anyway, I agree, an engineer is very helpful in Payload maps even in those first few minutes. Perhaps an option to limit the number of engineers would be better.