As is my wont, I'm going on a baseball park binge (I'm trying to get them all seen). This July, I'm seeing the 'parks for the Mariners, Diamondbacks, Angels, Dodgers, Athletics, Giants, Padres and Pirates. (In September I'm taking my usual 2-week trip to New York City.)
Whenever possible I go alone because I like to have time to explore the city on my own. But sometimes I use
Sports Travel & Tours. They are totally awesome, I highly recommend them. Main reason I'm using them this year is that some of the ballparks I'm going to (such as Angel Stadium and Dodger Stadium) have no mass transit access and no nearby hotels, and I refuse to waste my vacation time driving in an unfamiliar city.
The tour I'm taking is Dbacks/Angels/Dodgers/Giants; I'm adding on Mariners before it and Padres/Pirates after. This comes in handy because I will have plenty of time in Seattle to visit the Pike Place Fish Market and get hit in the head with a flying trout

and also must see the first Starbucks ever built!
ST&T takes care of everything. They fly - or sometimes bus - you from city to city, they take care of your tickets, everything. Sometimes they even give you a tour of the city - on this trip I'm going on, they give bus tours of L.A. and San Francisco. Can't go wrong with that! The only thing they don't do is get you to the first city on the tour, and get you home from the last one. You have to do that yourself. But that's a minor nitpick...and totally understandable. Small price to pay!
I am confused about something though. Why the hell does it take TWELVE HOURS to take Amtrak from San Francisco to San Diego? They're only 500 miles apart! I love trains, so I wanted to take one from SF to SD (the tour ends in SF), but then they throw that in my face. Oh well, at least the flight only lasts an hour...