hmm I'd imagine hitching from NYC to LA would take a long ass time if you wanted to do it in an organic way...probably for the best with that route you linked up with a rideshare here or other sites
Wowair is a good option
check Spirit Airlines also, it's a USA based discount airline you may find that to be in your interest 1. get your flight to NYC 2. get a spirit flight to LA or close (vegas, portland, etc) 3. begin hitchhiking
you will spend more on the road between the northeast and southwest than a simple flight, yes absolutely but it may also be in your interest...you could swing through many different cities, historic and/or college towns, countryside areas, national parks/forests...assuming you are not only really interested in LA and NYC