You can get to the MTA Subway line by taking Amtrak or Metrolink from the Anaheim station to Union Station in L.A., but one of the other options on that page might be more convenient.
We are taking Southern California Gray Line. Transfers run from 7am-9:30pm from hotel to the park. Phone is 1-714-978-8855 and call a minimum of 48 hours in advance to make arrangements for the transfers. HTH
and got our USH tickets through them and the price includes a round fair bus ticket there and back. Call up Gray line, tell them where you are staying, what day you want to go to Universal Studios and the Gray Line Bus will give you a pick up time and then pick you up from your hotel and will take you to USH, and as soon as the park closes they will pick you up from the park and take you straight back to your hotel.
Mind you they have other USH packages which also include and LA tour, or you can get tix to Sea world, Zoo, Lego Land, Medieval Times Dinner, Pirates Dinner, Knotts etc.
But all those packages include the round fair bus as well. Keep in mind that if you find that the tix are cheaper else where it is because they dont include the round bus trip. You have to pay like $15 exta per person (That being adults cost) through Gray line for the transportation but its well worth it. Good Luck