How to balance the baseball schedule

Starting in 2013, the AL and NL will have 15 teams apiece. The biggest change to the schedule means there must be an interleague series every day, as opposed to bundling it up in on block. How will this work?

Well, there is a way to now have a balanced schedule, meaning each team will be similar schedules. Here's how:

Each team would play nine home games vs. its four divisional opponents (9 games x 4 teams = 36 games).
Each team would play three home games vs. the other 10 teams in its league (3 games x 10 teams = 30 games).
Each team would play would play three games vs. five teams for the other league (3 games x 5 teams = 15 games).

36+30+15= 81 games (double for road games).

It would be simple enough to have a divisional rotation for interleague play, similar to the NFL. However, there are eight regional rivals that would need to be protected, so those teams could play every year (SF vs. Oak; LAD vs. LAA; ChC v. ChW; NYM vs. NYY; Cin vs. Cle; Mia vs. TB; StL vs. KC; Was vs. Bal).

This will require a tweaking of the interleague teams that are opponents. Because, now that Houston is switching leagues, all rivalries play for similar divisions (West vs. West, Central vs. Central, East vs. East). When that is in the rotation, no tweaking is required. When the rotation is West vs. East, Central vs. West, East vs. Central (or West vs. Central, Central vs. East, East vs. West), some changes are made. Taking the first pairings and the Giants for example, they would normally play home-and-home's with:

Baltimore, Boston, New York, Tampa Bay, Toronto

But to preserve the rivalry with Oakland:
Baltimore, Boston, New York, Tampa Bay, Toronto,  Oakland

This would cause a chain reaction, involving up to 22 teams. Replacing Toronto with Oakland is arbitrary (it could be any of the AL East teams; it would be have to be done in a 15-year rotation as to which team is "out").

Now for Oakland (vs. NL Central):
Chicago, Cincinnati, Milwaukee, Pittsburgh, St. Louis, San Francisco

Toronto (vs. NL West):
Arizona, Colorado, Los Angeles, San Diego, San Francisco, team TBA
The replacement team can be figured out after going through the chain reaction, and find the NL team needing an AL pairing.

The chain continues:
St. Louis (vs. AL West):
Houston, Los Angeles, Oakland, Seattle, Texas, Kansas City

The chain would continue with Kansas City, and so on (to make sure the other six remaining regional rivalries are matched up correctly). If the schedulers really wanted more work, they can separate the teams "crossed off" for the home and road series (ie The Giants miss Toronto at home, but play them on the road, and skip Baltimore).