Take me out to the ballgame has a little extra meaning for Terri O’Brien of Lynn and her 82-year-old mother, Louise Creamer.The mother-daughter duo have been on a mission to visit every Major League Baseball park and with 18 already on the “done” list (including Fenway) and two more on the docket this season, they’re well on their way to reaching their goal – and they have the T-shirts to prove it.Creamer, a lifelong Red Sox fan even though her late husband, Melville, was a Yankees fan, mentioned off and on over the years how she would love to see the Toronto Skydome some day. O’Brien socked the idea away until 1998.”That Christmas I got a card and she had written on it “as soon as he tickets go on sale I’m going to take you to Toronto to see the Red Sox,” Creamer said. “When the next Christmas came around, the same thing happened and that’s how it all got started.”So where has Terri and Louise’s Ballpark Adventure (that’s what the T-shirts say) taken the two?After the Toronto SkyDome in 1999, it was on to Alanta’s Turner Field (2000); Baltimore’s Camden Yards (2001); New York’s Yankee Stadium (2001); Tampa Bay’s Tropicana Field (2001); Milwaukee’s Miller Park (2003); San Francisco’s SBC (2004); Philly Citizen’s Bank Park (2005); Chicago White Sox U.S. Cellular (2006); Arizona Chase Field 92007); Cincinnati Great American Ballpark (2008); Anaheim Angel’s Stadium (2009); Seattle Safeco Field (2010); Pittsburgh PNC Park (2011); Miami Marlins Park (2012) and Detroit’s Comerica Park (2013).Fenway Park is a given.This season, O’Brien and her mother plan to add two more parks to the list. They’ll be heading to Houston’s Minute Maid Park and the Kansas City Royals Kauffman Stadium. Although the two are on a quest to visit every MLB ballpark, there is one requirement before they book the trip. The Red Sox have to be in town.Not that they play favorites, but some parks are better than others. Creamer, who lives in Peabody but grew up in Lynn and raised her family in Lynn, puts Camden Yards at the top of her list (not counting Fenway, of course).”I kind of think Baltimore was the best,” Creamer said. ‘It’s a nice little stadium. It reminds me of Fenway. It’s small. Some of the other parks are so big.”Camden Yards also got points because the day they were there, it was extremely hot and as a result, everyone was offered a free bottle of water.Although they have taken in the sights in some of the cities they’ve visited, the focus is really on game. O’Brien said the year they went to Toronto, they had planned on taking one day to see Niagara Falls and a few other local sights, but they got talking with some people who couldn’t use their tickets (they had box seats) the next day and they offered them to O’Brien and Creamer. They snapped them up.”We figured Niagara Falls wasn’t going anywhere,” O’Brien joked.Creamer said she grew up liking the Red Sox. Her father was a Boston Braves fan and he would say “you’re going to see the bums again.” When the Braves left down, he joined Red Sox Nation.Creamer said she and her daughter (she also has a son, Steven) joke about stepping up the pace in visiting the parks.”We joke about getting up in age and that we’ve got to see at least two a year,” she said. “We do have a lot of fun together. We’ll go out and eat, have a couple of beers and then the ballgame.”When they go to Houston this year, they’ll also be celebrating Creamer’s 83rd birthday. On her 75th birthday, O’Brien had Happy Birthday Mum, Louise, put on the billboard at the Chicago White Sox field. She couldn’t put any Red Sox comments on it, but she added “Go Sox.””We knew what it meant,” O’Brien said.