My recommendation needs to be avoid AI. They aren't reliable. I got good crews, but got busted planes, bad service on the ground. Food is not bad though - there is something about good chicken tandoori.
On UA - forget it. Both flights out of EWR are usually badly overpriced. I guess the seats are selling briskly from EWR.
East coast, J should not set you back more than 3k-4k. AC and LH and LX are good options through Toronto, Vancouver, Frankfurt, Munich and Zurich. Asiana may be affordable, ANA probably less. SQ, well, that's luxury!
A quick search on the Web for flights out of LAX Mar 9th->16 shows United/Lufthansa and Air Canada options available for $3.7K (seems it is Priceline, so I don't know if it books in 016, probably not, but usually the miles are coming in). That is not the cheapest. The absolute cheapest is China Eastern for $2.1K. Their service is not bad, their hard product at least out of JFK is superior to United except for the new Polaris.
So, if I were you, I would shop. M class doesn't seem the best option.