Ha! Finally did it, but with a few changes.
I used my privateer to take the two ports and my infantry to take the factory as
Jean-Luc Picard , said. Then I departed from the strategy from there.
I would have just taken my infantry south to the Mediterranean as usual, but after taking the second port, the Ottomans were still allies, and since I didn't want the Russians to come south and take out Brueys, I detoured to the tier one stables and took that. That did the trick, Ottomans neutral and Russians now staying north to attack them. That would've been an unnecessary step had the Ottomans turned neutral before that.
So next I landed them on the empty british hex you see in the middle of the Delta. Next turn, I moved one hex east and placed a tier 2 fort on my landing spot. Moved east one hex again and built a coastal fortress where you see it in the screenshot. Meanwhile I had Brueys trapped in his port with my four remaining ships (minus Nelson whom I just took far out of the way to safety). Once Brueys was done feasting on my weak remaining fleet, he attacked the fort and eventually destroyed it, but not before I got my infantry around behind the French infantry one hex at a time, you can see the path I took. I built a trench, then helped the coastal fortress kill the French infantry with mine.
Brueys decided not to attack the coastal fortress presumably because I had taken Nelson back south just within reach of him and that was enough bait.
So after pounding the infantry to death, voila!
You can see in the second screenshot, five farms have been taken in one turn. You will need a general with high movement and/or movement items to take all five though.