To those of you who have lost loved ones to melanoma, I am so incredibly sorry for your loss. But, Maria, Stage IV melanoma doesn't ALWAYS equal a death sentence. A close family friend was diagnosed with Stage IV melanoma last year, and she went through a few rounds of biochemotherapy, and her cancer is now in remission.
No, it's not that easy (yeah right, like biochemo is really easy!) for everyone with Stage IV melanoma. My Dad was diagnosed with Stage IV melanoma in October 06, and he's still fighting. He has mets pretty much everywhere in his body. You name an organ, he's got mets there. Three rounds of biochemo kept his cancer from spreading and growing, but it was too hard on his body, so the doctors took him off of it. He has since tried several other combinations of chemo, developed some brain mets, had stereotactic radiosurgery for them, and is now going through another round of chemo (dactimycin, carmusine, and hydroxyurea), which has been the first chemo he's taken that's been effective in shrinking some of his tumors (x-ray results only - he isn't due for another full scan for another few weeks).
I don't know why doctors give the 6-12 month prognosis, when they really have NO idea how a patient will react to the treatments given! Some people get stage iv melanoma, and they don't make it a month. Others live for years (we know a guy who was diagnosed with Stage IV melanoma over 15 years ago!).
To answer your question (based only on what I know of this disease), if your mom is going through chemo right now, chances are, she won't WANT to go anywhere. I'd advise bringing the family to her (but be careful about sick family members - especially kids - and ask the doctor about babies and children who have been vaccinated within the last 6 weeks - live vaccines are contagious and very dangerous to someone on chemo with no immune system!).
If you haven't yet, make time to have a conversation with your mom and get some feedback from her on what she wants. Hope this helps.