Empty nester here, but I would say our income was in the $200 - 230 K range when the kids were at home. On average, we probably spent $20K on travel, some years more, some years less.
I don't think any of these are "must-do" trips before college, but we enjoyed the national parks in Western Canada, MA, NH, NYC, OBX, HHI, Kiawah Island, WDW, California coast/Yosemite, other national parks like Grand Canyon, Grand Teton, Yellowstone, Acadia. And in Europe: London/Southern England, France, Italy, Switzerland, Germany, Austria, Scandinavia, Belgium, Netherlands, Ireland. Some of these were multiple trips, like Switzerland and Italy. One we wished we had done with kids: Australia, but the school schedule here would have meant visiting in winter there, and you need more than a spring break week.
P.S. While it does get more complicated, we do still travel (some) with our adult children, so don't feel like you have only a few years left to hit some bucket list places.