SFO/LIM is being suspended end of March. Your only lie flat (or close to flat) option the entire way is EZE/JFK/SFO. From time to time there are widebody AA services that connect via MIA or DFW, but not always, so you can get stuck with a 5+ hour westbound transcon sitting up in domestic F after a red-eye. AA is starting GRU/LAX soon, so maybe you can find some award space there with short EZE/GRU and LAX/SFO tags on either end.