The best way would be to buy tickets to fly where you want to be. 1800 is a lot, and it is hard to make that much on partners flights. It is true that partners flights can yield more PQP than UA, but it is usually applicable to very discounted fares on long routes. I am yet to see a business TATL fare which would yield anywhere close to 1 PQP per dollar. In short, I do not think you have a lot of options here.