This is a scattered, cumulative account of my travels, by decade, by state, province and country, in rough order of first visits to each.
1950s
Ohio, Pennsylvania
1960s
West Virginia; Ontario, Canada; Maryland; Washington, D.C.; Virginia
(Baseball: Cleveland Municipal Stadium)
1970s
Michigan, Kentucky, Tennessee, Georgia, Florida, South Carolina, North Carolina, Louisiana, New York, Massachusetts, New Hampshire, Connecticut, Rhode Island, Vermont, New Jersey, Delaware, Maine, Wisconsin, Illinois, Iowa, Missouri, Kansas
(Baseball: Fenway Park, Milwaukee County Stadium)
1980s
Nebraska, Colorado, Indiana, Oklahoma, New Mexico, South Dakota, Minnesota, Texas, Utah, Washington, Oregon, Idaho, Wyoming, Montana, and British Columbia, Canada
(Baseball: Wrigley Field, The Kingdome)
1990s
Alaska, California, Nevada, Arizona, Hawaii; Quebec and Alberta, Canada
(Baseball: Candlestick Park, Oakland Coliseum, The Big A/Edison Field, Jacobs Field)
2000s
Baja California, Mexico; Singapore; Bali, Indonesia
(Baseball: Yankee Stadium, Skydome, Shea Stadium, Busch Stadium, AT&T Park)
2010s
(Baseball: Kauffman Stadium)