First timer post--love FT!

Neither Chase Continental OnePass Plus or Chase Sapphire Preferred alone will give you the 65K bonus miles on United. The BA Chase card will give you 50K bonus miles enough for the round trip flight to South Korea on Japan Airlines but you need purchases totaling $2500 in 3 months, and with a $95 annual fee. One main drawback are the taxes on Japan Airlines; North America to Asia (Far East in BA award table), taxes are around $450, and adding the annual fee on the credit card--it's around half the ticket price in economy. Also you need to be flexible with your schedule for award bookings. Bottom line: it seems like too much trouble for one reward round-trip in a short amount of time.

I have to agree with lwildernorva, getting a new reward credit card now is for next year trip planning. You may need to get one additional rewards credit card to get enough bonus points. This is probably not the the venue for financial planning but evaluate your credit card expenses before incurring credit card debt for the glory of collecting airlines points or miles.

I was in Seoul in May 2011--my first time and loved it! It's is a wonderful country with very friendly people and tasty food. I don't speak Korea but a lot of people understood English. I think I paid under $700 from one of the posting in the mileage run deals thread. Expect to pay around the same in October and early November hopefully it will be cheaper.

Hope this helps.