Colonial Williamsburg, the largest living history museum in the US, makes just about every family's must-visit list.  And it's easy to see why: this reconstructed 18th-century Virginia capital brings to life one of the most important periods in American history, with a cast of thousands dressed in period garb playing the roles of colonists.  The best part?  Kids have so much fun they don't even notice that they're learning.

This summer, Colonial Williamsburg is offering a Summer Saver package that includes four nights lodging, park admission, and a credit to spend a variety of ways. The package price starts at $599, based on a family of four with two kids 18 and under. To see if it's really a good deal for families, we did the math. The package includes:

• four nights in a standard double room at the Williamsburg Woodlands Hotel & Suites (worth $596 in mid-July)
• daily continental breakfast at the hotel (always free)
• length-of-visit admission passes providing unlimited access to Colonial Williamsburg's Historic Area, including all exhibit sites, street theater program Revolutionary City, indoor art museums, historic area shuttle and hotel parking (worth $30 x 2 adults + $15 x 2 kids = $90 for four-day guest passes)
• 25% discount on Colonial Evening Program tickets (saves about $15 x 2 performances = $30)
• $100 credit, good at Colonial Williamsburg shops, restaurants, spa, and recreation facilities

It's important to realize that, even without the package, families who stay at official Colonial Williamsburg hotels save a bundle on park tickets. A family of four staying at an official hotel can purchase mulitple-day passes for just $90, where a family staying elsewhere would shell out $108 for a single day ($36 x 2 adults +  $18 x 2 kids). Over several days, the savings can add up to hundreds of dollars, and allow you to enjoy the historic area at your leisure.

If booked without the package, four nights at The Williamsburg Woodlands Hotel & Suites plus unlimited access passes to Colonial Williamsburg for a family of four would come to $686, so this package saves another $87 right out of the gate.  If the family is smart and uses the credit to purchase meals, that will cut the price of the vacation by another $100, for a total of $187 saved.  While the discount for the evening performances is appreciated, it applies to an optional expense for which the more you spend, the more you save.

Deal or no deal?  Staying at an official Colonial Williamsburg hotel saves money on admission from the get-go. In mid-July, this package can lop off another $187 on a vacation for a family of four when the $100 credit is used on essentials, such as meals.

Note that the lowest package price is good for a Sunday or Monday arrival; a Friday or Saturday check-in boosts the price by $50. There's also a range in regular lodging rates during the summer, from a low of $436 for four nights in late May to a high of $606 for that stay in mid-August.  Since the package price is fixed, you save a smidge more money by visiting during peak seasons—but that also can mean that you'd have to deal with bigger crowds.

The package is valid from May 31 to September 2.