Follow these guidelines to ensure a fun and relaxing trip. By Vera Gibbons May 31, 2007 A vacation home can be great for families and large groups. But know what you're signing up for. Here are five costs, policies and circumstances you should anticipate.1. Beach? What beach? You went online and found a listing for a waterfront cottage that sounded perfect for a vacation getaway. But when you got there, the house wasn't anywhere near the water. Hundreds of Web sites now list rental properties, and, says Emily Glossbrenner, coauthor of How to Make Your Vacation Property Work for You!, there are "many instances" of such tall tales. Always book through a reputable site -- such as Vrbo.com or HomeAway.com -- that provides pictures, contact information and insights from past renters. 2. You'll pay extra for Grandma. Renting a vacation home is the most affordable and convenient plan for large families. But beware of hidden costs, such as fees for additional guests, pets, house cleaning, air conditioning and Web access. To eliminate surprises, make sure all these details -- plus your move-in and move-out dates and payment schedule -- are spelled out in a contract. At the very least, says Glossbrenner, get it in writing in an e-mail, "so you have a paper trail if you need to go to small-claims court." 3. The baby has a fever? That's too bad. Don't expect a refund. "There's no level of protection in this industry," says Brian Sharples, chief executive officer of HomeAway.com. "You can try to get your money back, but owners and managers will rightfully say they can't give it back." Typically, if you cancel within 30 days of your stay, you will lose all the money you've paid. If you think you might cancel your plans and get stuck with the bill, buy travel insurance. To compare policies, go to InsureMyTrip.com. Figure coverage will run about 5% of the total cost of your trip. Advertisement 4. Your new best friend likes Liza with a z. Going in on a group house is an ideal way to cut costs for a summer-weekend getaway. But it could cost you your sanity. Just ask Pierce Mattie of New York City, who spent many sleepless nights at his shared summer house on Fire Island. Why? Because his seven housemates blasted show tunes at all hours. Now Mattie won't go in on a group house without written guidelines that spell out everything from the schedule to sleeping arrangements to how costs will be shared. 5. Renters are slobs. Owners have their problems, too. "The most common complaint is cleanliness," says Christine Karpinski, author of How to Rent Vacation Properties by Owner, who has rented out her condo in Panama City, Fla., for more than ten years. "The same people used to call me year after year to tell me about all the cleaning they had to do when they got there -- that there were Pringles underneath the couch or something," says Karpinski. She recommends including a cleaning fee in the price of the rental and requiring a reservation deposit that converts to a security-and-damage deposit when renters arrive.