Nice. It's so interesting to see how people do these, and thanks for trying to avoid the 'cookie-cutter' type of schedule. This probably doesn't affect anyone else, but it breaks the immersion for me when, for example, a whole 8-team division is always playing within the division or out of the division together. Creating a schedule should be just as much art as science.
When I was doing the other 60-team schedule this is what the meat of my spreadsheet looked like. I do one series per cell rather than one game per cell so I can see the whole thing at once, then transfer it later.
You can see the matchups for each series in the first table - green are division games, yellow are interleague. The gray table is where I actually put the XML for each game a bit at a time. It has the last set of games in there right now, which are the Thursday games for each 4-game set. I set it up that way so that I can do as little typing as possible.
The blue and orange one is home versus away. Blue is home, orange is away - I decide these after I do the matchups so sometimes a team will get forced into a super long trip.
Last one, which you can only see a bit of, is length of series. This is what I actually do last. In the case of this schedule, the only 4-game series were against division opponents, so any cell in there that's blank is automatically a 3-game set.
I set this one up so that I could just double a 30-team schedule to produce the 60-team version. I'd never done that with interleague before - every new schedule is a new feat of engineering it seems.