Welcome to the group, @GavinCh - ask away any questions that may help you and Karen thru this. Your support for Karen will be a real asset in helping her thru this - as well as the kids' support.
Once you've seen the team & had the tests & biopsy etc you'll have a clearer idea of a Plan of action. There are lots of 'waits' as you wait to see the team, wait for the appointments, wait for the results, which can do both your head in a bit as well as Karen's?
Yep, keeping busy is really good (in my books - it worked for me!) I have a few hobbies that I buried myself in - and they were my saviour.
Re the holiday - I saved mine til after I'd finished my Rads (this time last year.) I went to Norfolk Island with some Ukulele buddies! :)
Just be mindful of how Karen is coping. It is both mentally and physically demanding. There will be good days, there will be tough days - but both you and Karen can do this xx
Where abouts are you (Town/City?) Others may have info on services that are near you xx