In levelling my alt, I did Zion 8.2, 8.3, and 9.1 over and over ad nauseum. The first phases for each of these does not require you to enter combat at all. For 8.3, the first three phases do not require combat. 9.1 also ends with either the last two or, at least, the very last one not requiring combat. 9.1.2 requires a lot of combat, though. It's a good fairly balanced way to go about grinding, and it got me through the grind from 30 to 50 pretty quickly at about a level a day.
If you're worried about getting maximum experience on missions without combat, make yourself a timer macro.