Sprawl Wilds averages at about 4 karma, if Shooting Line does the same and we get 18 Season 5 Missions at average 7 karma each then retiring would require near-optimal completition of the entire thing and that's assuming you do them all. So perhaps retiring won't even be an option yet. Can't wait to see, by the way.
Actually, sprawl wilds should cap at 6, 6, 8, 6 karma for a total of 26. Although "by the module" they only give 3, 3, 5, 3 because they karma section was written for 4E, Bull has stated that the 5E karma rules should be used utilizing the caps from the module (which is where the 6, 6, 8, 6 comes from.) I'm hoping shooting line addresses this to make karma clearer when playing under 5E, but once Bull gave us a ruling, we were good to go on karma with Sprawl Wilds too.
I'm also assuming that any karma gained by "working for the people", which is basically an extra 5 per mission as long as you have the Nuyen for it, would not count, although that makes things very tricky on tracking karma. I'm trying to keep very detailed records of this so that when a ruling does come out, I will know how to apply everything. If working for the people and working for the man are meant to be karma modifiers that affect retirement, it gives too much ability to manipulate, since you could just work for the man and basically go on forever.
Assuming 6 karma per module: We'll have (4 + 4 + 18) *6 = 156 karma without working for the people being taken into account. Since some modules will cap higher, I think 150 is very doable within 26 missions. If you are doing CMP's, then the number of missions goes even higher, making 150 karma more of a certainty.