Where to hold your family reunion depends a lot on what type of reunion you choose. If you chose a "picnic" style, you can do it in someone's backyard and you're likely to do it nearby. If you choose a getaway weekend or a full-fledged vacation, you'll likely want to travel somewhere a bit more exotic.
Most people choose a geographical location for their family reunion for one of these reasons.
Write down your top three choices for where you'd like to hold your family reunion. Make a note of why each place appeals to you and put a star next to your top choice (if you have one).