I know you can't call any way the "best" way, but for instance, I would enjoy an order where people chose one mission before another for a strategic reason for achievement purposes.
For instance, reapers are really good on Outbreak for the 15 buildings on night, you can take them out so fast. I didn't know this so I began to think what more of these are there.
I wonder if its a order for this for upgrades as well. Again the +dmg reaper upgrade is really good on Outbreak.
I would love this so I could blast through all the missions the fastest and easiest way.