My girlfriend of 1 year decided we needed a break to find herself and go her own way in life. Should I take her out tonight for one last date? Or leave it be for a couple weeks after NC, or should I forget it all together

Is this a good idea or a recipe for disaster?

Forget it all together. There is no point in having "one last date." That is is an excuse for you to try and see if you can't change her mind. Doing this would just cause more pain. When they say "I need a break" or "I need to find myself" then it is over. The best thing you can do is begin the healing process. Sorry for your loss and good luck.