On a recent family trip, I found that my best-laid plans to keep costs under control were thwarted. Thinkstock By Cameron Huddleston, Former Online Editor October 10, 2014 I thought my careful planning would save my family money when we took a vacation this past week. But you know what they say about best-laid plans …SEE ALSO: 26 Secrets to Save on Travel Our week-long trip involved flying to Salt Lake City, then driving to Yellowstone National Park and Grand Teton National Park. I booked our flights early enough to score the low fares on Southwest Airlines for the particular route we were taking. Plus, I had enough frequent-flyer points to offset the cost of some of the tickets (see How to Earn Airline Miles Without Flying). And by flying Southwest, we would be able to check up to two bags per person for free. However, our flight was canceled the night before we were scheduled to depart because we were flying through Chicago, where a fire at an air traffic control center disrupted air travel across the U.S. When I saw the e-mail notifying me of the cancellation, I called Southwest while my husband started searching online for flights on other airlines. After staying on hold for more than an hour, I finally spoke to a customer service representative who gave me a full refund for our canceled flight. And my husband managed to find a flight to Salt Lake City on US Airways for about $40 more per ticket than our original Southwest flight. Although we took a hit, it could’ve been much worse. But then US Airways charged us $25 per checked bag. So we were out $75 for three checked bags. Carry-ons weren't an option since we needed several layers of clothing for the five of us to wear in the mountains, as well as a large hiking backpack to hold our toddler during treks along trails. Advertisement I packed snacks to take on the plane, but we ended up buying a meal at the airport because we had to arrive before lunch for the first leg of our flight, then wait three hours before the second leg, which departed right at dinner time. Then our first day in Yellowstone, we had to buy hats for the kids. I didn’t pack any (even though my husband said I should) because the forecast was calling for highs in the 60s. But there were high winds, and it didn’t get much above 50 degrees. Fortunately, though, my planning did help offset some of the additional expenses we incurred. Because our original flight was scheduled to arrive in Salt Lake City late in the afternoon, we had decided to stay the first night of our trip there before heading north the next day to Yellowstone. We also needed to book a room in Salt Lake City the night before our return home because we had an early flight. So I took advantage of points I had racked up with a hotel-branded rewards credit card to get two free stays at a hotel with free breakfast (see our picks for best hotel rewards cards). Advertisement My husband took advantage of a discount through his employer to get a deal on a rental car. And because we would be going to Yellowstone and Grand Teton, the only thing we had to pay for four days of sightseeing was a $25 fee that covered the entrance to both national parks. If we had gone in the summer, we would’ve camped to save money. But with temperatures forecasted to drop into the 30s at night, and the bears in the parks in the process of fattening up ahead of winter hibernation, camping with three young kids wasn’t a good option on this trip. We booked a room in one of Yellowstone’s lodges for two nights, then took advantage of off-season rates at a lodge (with free breakfast) in Jackson, Wyo., near Grand Teton. We also packed reusable water bottles so we wouldn’t have to pay for overpriced bottled water. We also brought a collapsible cooler that we filled with food purchased before entering the national parks so we wouldn’t have to pay for high-priced meals within the parks (see more ways to cut the cost of travel with kids). And we told our two daughters beforehand that they had to use their own money to buy souvenirs. Our 2-year-old has no money of his own, so he didn’t get a souvenir. But he did get to see Old Faithful, waterfalls, snow-covered mountains, elk, bison, moose, wolves and even a grizzly bear. That’s better than any souvenir, right?