Figure in Child Care
If you're not traveling with another family and you and your spouse hope to spend some time alone, plan ahead to make sure you'll have someone to watch the kids. Hotels may maintain a list of qualified babysitters, and some even include the service with the cost of the room. If the hotel refers you to an agency, call to ask for references from other travelers, and request to speak to the sitter it assigns you before you arrive. If you're staying in a condo, try calling a nearby reputable hotel for recommendations. Some resorts have full children's programs that offer supervised entertainment, like pizza and games, so you and your spouse can have dinner alone. If you feel uncomfortable leaving your kids with a stranger, consider bringing along another family member to help. Your children might prefer their grandmother (especially one who lives far away) or a teenage cousin (who may be happy to trade a few hours of child care a day for the trip) to an unknown babysitter. Another option: Hire a mother's helper to accompany you so she can play with the older kids while you give your undivided attention to your toddler (go to Craigslist.org and look under "Community/Childcare").
Tip: When you arrive at your hotel, take the kids on a quick tour. Show them the front desk, and explain this is where they should go if they get lost or have a question. And point out house phones they can use if they forget how to find their way back to the room.