Just got back from first family cruise-so easy to do with a family. In fact just booked another for 2021.
Kids favorite though is from younger when we would stay at our "treehouse" condo timeshare at Lake of the Ozarks. Just hang out, swim, boat etc. Condo looks like the treehouse villas at Saratoga springs, but ours has 3 levels (including upstairs loft bedroom with 1/2 bath and lower level with bedroom and full bath). Now that we live closer and In-laws have house on lake shore we trade it out to travel. Have my request in for France next spring (middle DD's grad trip wish!). We've gone to Disney a bunch past few years(have a kid who did two DCP's), and I think the younger kids favorite time is more hanging out at resort now when we trade into Marriott resorts in Orlando.
ETA-I grew up around Mount Rushmore, family trips to Yellowstone, including a stop at Devils Tower, etc, and on our family's list to travel to soon. And a mom/dtr trip to DC was so fun-would love to go back. Smithsonian Museums are simply incredible!