[ElaineM]

I am so sorry to read your latest news. I would ask the oncologist for the Tykerb in addition to the Gamma Knife or other radiation techniques you are considering. Tykerb is known to pass the blood brain barrier and may help shrink the brain mets. Tykerb is in pill form, so you won't miss any treatments if you start it before your trip. You can continue to take your daily dose no matter where you are in the world.
I hope the latest news won't interfere with your trip.
I don't know what arrangements you have made with the radiologists for gamma knife in Hawaii or which medical center you are planning to visit for the gamma knife treatment. You might want to consult them or have your latest test results faxed to them before you arrive, so they can prepare for your visit.
You might also enjoy a change in the climate since you are probably experiencing winter while we are in the middle of summer.
Take good care of yourself.