Reserve America is the website to use when you want to camp at any national or state parks. It is easy to use, giving you a map of campsites to choose from and a calendar to find available dates. The best part of camping in our national or state parks, besides the obvious beauty, is the price. Most campsite are around $30 - $40 a night. Perfect!
Hipcamp is great. It is like the Airbnb for camping where people list their land for others to rent. I've seen some amazing places available on there like camping in the middle of a vineyard or by a creek on acres of land with no one else around. Very cool and useful website.
I love airbnb! Renting an apartment or house when your are traveling with your kids is the best - you get a kitchen and mutiple rooms so you have a place to hang out after the kids have gone to sleep and you can meet some amazing people. We have used it in many places but I definitely think it's best when you travel to Europe, where hotel rooms can be pretty tiny.
When we do stay at hotels, we book them with hotels.com. I am not snobby when it comes to hotels and usually am just looking for the best deal going. This site is great because you can read other guests reviews, see pictures of the hotel, and map out where it is all while comparing prices and star ratings. Plus their app works like a charm.