So I need to go to Korea for something and I found a pretty good fare through Singapore Airlines (SFO-ICN) for $929 all in round trip (W class fare). It works out pretty well, because I'm going to be in California once I come back. Problem is, I'm in NY right now and will have to buy a one way ticket to SFO. The flight leaves SFO at 2:15PM and I found an AA flight that leaves Kennedy Airport at 7AM that will get me into SFO at 10:15AM, with plenty of time to spare before the SQ flight (theoretically). What are the risks involved with this kind of itinerary and what can I do to mitigate those risks? I'm afraid the AA flight will get delayed or cancelled or something and I'll end up stranded at JFK while the SQ flight leaves without me, and end up having to pay some exorbitant fee to get on a different flight. I absolutely need to be there on May 15th (I have something important to tend to on the 16th) and I absolutely CANNOT leave before about 7PM on the 13th. Should I play it safe, take a night flight to SFO, and go home in Monterey and then come back up to SFO the next morning? Should I cough up the extra $200 for a multisegment itinerary? (It would be JFK-ICN-SFO)

I'll be charging both itineraries to my American Express card (If I do buy...I haven't bought yet), which I guess offers some kind of travel insurance, but I'm not sure what exactly it is. I think the SQ fare is here to stay for a good week or two, so I'm not all that much in a rush to buy, but I just want to know what the risks are for traveling with 2 separate itineraries. Does Amex offer any kind of protection in cases like this where one flight gets delayed and results in a misconnect?