I had alts placed with tents at SF mine, V15, Themepark, and Waterworks.
Depending on Action Points, it would take 1-3 minutes to get 25 EP from Themepark and SF mine (each).
V15 you only need to kill the stuff on upper level- I had a melee alt with Bonus HTH attacks, little jesus, and 8 AP. Took him 1-2 minutes to run across map, enter V15, kill everything. Then 2.5 minutes for the EP gathering - 2 consoles for 50 EP. Say 5 minutes total time including running back across surface and dropping stuff in vehicle at tent.
Waterworks is bigger, but if you only go for EP, it should only take about 6-7 minutes. If you go for Chemical Components, the excursion (with 10 AP alt) will take about 12+ minutes.
So jumping from alt to alt and grabbing everything would take me 13-26 minutes depending on if I want all the CCs.
I would skip Waterworks often, but the others were faster.
At least once per day I would get WW and SF Mine- only 5 minutes or less for 50 EP/day.
-SwinglineRed