I've been searching all over flyertalk for info, and there is so much... almost too much.

I just had a flight from HKG-LAX-SLC with a return SLC-SEA-HKG purchased through Delta with a codeshare from Korean Air.

That trip alone got me ~15k miles on Delta SkyMiles, but with the reading I've been doing maybe SkyMiles wasn't the best choice.

In addition I have a United Milage Plus account with 8,500 miles that I got from a round trip ticket JFK-SFO-PEK but I didn't go back, so I only got half of the miles... United tells me that if I go back to PEK and want to fly to JFK
I can pay a small fee to have the ticket date changed, but I cannot change the itinerary.

I also took two flights on China Southern that I haven't redeemed for miles that I might be able to get something out of.

In December I've got a one-way multi-city from HKG-TPE*-NAR-HNL-SFO-DFW*-GUA-MIA*-JFK with a 7 day stay in each city (except for the ones with *... those are just short layovers). The first leg is Cathay Pacific, second and third legs are are All Nippon, the rest are on American.

I travel for leisure, in economy. I'm not interested in upgrades just free tickets (in economy).

What recommendations do you have for me? Is there a place I can go to get an overview of the pros/cons of different FF programs?

Thanks!