Yes, it's easy to get to Hollywood from Disneyland. You will go north on interstate 5 to interstate 101 following the signs to Los Angeles then exit on Hollywood Blvd. The theater (recently renamed the Dolby Theater) in on the corner of Hollywood and Highland - impossible to miss.
We recently saw Iris at the Dolby Theatre, and were pleasantly pleased with the production. Be sure to arrive early, since cast members interact with guests before the show.
We have seen several Cirque shows and just want to say that we think IRIS is the best! I think you will have a great time. Just remember to factor in time for traffic (especially if you go on a week day). The front desk staff at Hojo's is so very helpful if you need directions.