The trick is I need to reissue anyway if I use the tickets; our planned trips fell through this year, so if I used the RTW it would only be for mileage accrual (how awful of me

). I had LAX-SJO open dated segments (and AA no longer flies this route). If I ended up not having to reissue for changing the CAI-LHR segment, would ~4 hrs be enough at LAX if I had enough time?
eg.
Sep4 CAI-LHR-LAX
* reissue
Sep4 LAX-JFK
Sep5 BOS-DFW-ANC-DFW
etc.