Since you're almost as far east as you can get, best bet is to do some north/south flying. See if you can go via MIA, then to ORD or DFW, then to PHX. Or, maybe you can do some backtracking via LAX. Use Expedia to look at the routing rules for the fare to see what you can do. As stated above, those of use in the Mileage Run forum can get you lots of miles for little buck.