They love to tell you all the secrets. Call a church or friend located near your destination and ask them about sites and activities. You'll pick up some great insider tips. If you have a friend who lives near your destination, consider swapping houses for a week. If you're interested and already have the equipment, include biking, fishing, backpacking, hiking, photography, tennis, and similar activities in your agenda.
Summer is a great time for bikepacking trips.
After you've gathered your information, make a big bowl of popcorn and have a family brainstorming session. List activities each of you would like to do. Especially things that are free. Forget hotels and restaurants as much as possible. If you do get a hotel room, try to get one with a kitchenette.