The A's and the Angels both have 35 games remaining. Who has the tougher schedule? The Angels. Let's walk through it...
Analysis shows that of the remaining 35 games, 23 are "overlaps." For example, in addition to playing 7 games against one another, the A's and the Angels both have 3 games left against Baltimore, Chicago and Seattle. In my analysis, I eliminated these common games and focused only on the strength of disparate opponents. Each team has just 12 of these disparate opponents remaining.
Relative to the A's, the Angels have one extra game left against Texas, 3 extra against the Yankees, Detroit and Toronto, and 2 extra against Kansas City. The weighted averaging current winning percentage of opponents in those 12 games is .546. To think about a .546 winning percentage, remember that right now the team with a winning percentage closest to .546 is the Red Sox, who have a .556 winning percentage.
Relative to the Angels, the A's have 2 extra games against Boston, 3 against Tampa Bay, 3 against Minnesota and 4 against Cleveland. The weighted average winning percentage of opponents in those 12 games is .493. The team with a winning percentage closest to .493 is the Giants, at .488.
Thus far, this analysis does nothing to consider overall home and away, strength of schedule home and away, or, for that matter, whose record may not indicate state of current play. Let's look at these quickly.
Overall, the Angels have 1 more home game left relative to the A's. So that's no big deal.
Of the "disparates", the Angels have 3 left at home against the Yankees, and the Yankees are a very good club on the road. The Royals are much better at home, and that's where they play the Angels. On the other hand, Toronto and Baltimore play much worse on the road, and that's where they play the Angels.
For the A's, they get Boston while the Sox are on the road, and where they have a losing record. Unfortunately, the A's do have to go to the Minnesota chamber of horrors. (I'd take 1 out of 3 there.) The A's also get Cleveland in Oakland, and the Indians are much better at home than they are on the road.
Finally as to getting teams where they are now, the A's and Angels have equally tough outliers: the A's have to play Minnesota, the best team in baseball since the beginning of May, whereas the Angels get the Yankees, who have been very tough since the break. The A's get Boston and Tampa Bay, both of which look like sinking (or sunken) ships, and 4 against a Cleveland team that is officially out of the race. The Angels get a tough 3 against (a cooler) Detroit club, and even 2 against a Kansas City club that is playing everybody pretty tough right now, especially in Kansas City.
No matter how you slice it, the Angels have the tougher schedule the rest of the way. What this analysis overlooks, of course, is that if the Angels outplay the A's in their 7 head to head matchups, none of the above much matters.