Greg,
My wife is in a very similar situation... stage 4 at dx, strongly Her2+ by FISH, and relatively young (37). She's a little more than a year into this. I would really agree with the voices on this thread calling for Herceptin to be added back into the mix (or at least looking at this strongly). The data does show that there is statistical benefit. As targeted therapy, my wife has Tykerb + Herceptin right now along with a standard chemo agent. There were some recent reports out of the Chicago seminar as well as the SA Breast Cancer Symposium in 2009 suggesting that H+Tykerb > Tykerb alone -->
http://www.rttnews.com/1154913/glaxo...dy-update.aspx. And, there are more and more studies emerging bearing out that combining multiple targeted agents in the treatment of metastatic Her2+ BC seems to be a favorable approach.
Also, agree that TDM-1 & Pertuzumab probably hold forth the most promise right now. And, there is definitely benefit from being close to a research hospital where you have access to clinical trials. However, one thing you should weigh is the balance between aggressive treatment and toxicity. By all accounts, Lord willing, these drugs will be available by the end of the year. It would make me think twice about jumping into a trial that would include a heavily toxic chemo alongside a drug like T-DM1.
As for scans, I'm not sure how critical 3 months vs. slightly longer interlude is in the overall picture (a clinical trial will require scans every 3 months or so), but I do think that it is important that you push for your wife to at least get fairly regular brain MRIs.