Well this is based on our experience RVing since the 90's and travelling when ours were younger (eldest now 32).
Our children experienced tons of varying destinations on many 10 day, 3 week and even a couple of 6 to 8 week trips we did from kindergarten until youngest rising 25 and still enjoys odd trips with us. They covered from North West down to Fla, everglade airboat rides, Dollywood, six flags at various locations, Oregon, California Coast, Vegas, many national parks and monuments like Grand Canyon, Death Valley, AZ Desert, Wyoming, Dakotas, Kansas, Kentucky etc etc. However, the key thing (most expensive lesson) we took away from every trip was the destination didn't matter - it was the fun, laughter and quality time we had together - oh the laughter and teasing when stuck closer to home ironically on rocks in rafts on 5 different rivers in Colorado; Dry Camping with a huge fire the night before rafting the Kicking Horse BC was wonderful; catapulting off seadoos, wake boarding and tubing, capsizing kayaks, snakes startling us popping up from holes under our steps when parked in California and about to get back into the RV after swimming on horse back in the ocean. Dad picking the girls up and throwing them around in the ocean in California and Hawaii, learning to surf in a fashion, camping in -35 Deg C in Rocky Mountain House Alberta whilst making snow angels, baking up a storm in the RV and smarty pants dad, getting the kids tongues stuck in the freezing temperatures to the metal handle on the hot tub, with mum close at hand to release with warm water whilst he couldn't control his laughter. Mean man, yet in their eyes daddy is their absolute idol and can't do any wrong!
Truly it's about the memories created being together - not the expensive theme parks or long distance destinations, that your children will treasure the most. At the end of the day, it's all about quality not quantity of time with your kids and creating memories and close bond relationships that will last a lifetime for not just you, but them as well.
You really don't have to go very far or spend much money at all, and none of us could ever see it all in a lifetime anyway. Believe me we tried (44 states inc Hawaii & Alaska), and now as we are readying to go FT retired by ourselves, we want to do it all again but at a pace slower than a snail of course. Can't wait to hopefully, one day be sharing similar experiences with our grandchildren and creating tons more memories and forging more ties that bond forever.
