This isn't meant to be anything really analytical (is that a word?), but I just looked at the remaining schedules for both teams, and then adjusted the winning percentages for each team they face against how often they face them. I know I'm going to get the weighing wrong, so please correct any mistakes. 

Number of games left, team, team WP%. The adjusted number percentage at the bottom is pretty much like the winning percentage for a hypothetical team if you played all your remaining games against them (though WP% doesn't fully accurately exhibit team talent, it's good enough I guess). Though to be honest, when I was calculating that it felt like it was a mathematical fallacy. But I get points for trying. The lower the number, the easier the schedule.

giants 44 games left (21 games at home, 23 on the road)

8 padres (.441)   

7 rockies (.466) 

7 astros (.325)

6 dodgers (.448) 

6 dbacks (.547) 

4 braves (.585) 

3 cubs (.427)

3 marlins (.470) 

Adjusted: 45.61%

dbacks 45 games left (23 games at home, 22 on the road)

10 padres (.441)

6 giants (.542)

6 rockies (.466)

6 dodgers (.448)

4 nationals (.483)

3 mets (.500)

3 phillies (.658)

3 braves (.585)

3 pirates (.483)

1 astros (.325)

Adjusted: 49.07%

Giants are going to have easier opponents from here on out, which doesn't sound good, but those six games head to head are still very crucial.

Actual series left:

giants 44 games left (21 games at home, 23 on the road)

3 @ marlins

4 @ braves

3 @ astros

2 padres

4 astros

3 cubs

3 dbacks

3 @ padres

3 dodgers

3 padres

4 @ rockies

3 @ dodgers

3 @ dbacks

3 rockies

dbacks 45 games left (23 games at home, 22 on the road)

1 astros

3 mets

3 @ phillies

3 @ braves

4 @ nationals

3 padres

3 rockies

3 @ giants

3 @ rockies

4 padres

3 @ dodgers

3 @ padres

3 pirates

3 giants

3 dodgers