Endgame content does not take that long to do once you get it. Most dungeons take 30-60 minutes to complete and the Coil of Bahamut takes much less. The fights are much more intense and mechanic-heavy, on par with primal battles, but none are 4-hour-long endurance slogfests. You could easily handle all of the endgame content runs most players do within 90 minutes.

As for endgame gear, you will be unable to grind tomes of mythology like hardcore players, but you should have no problem capping soldiery every week if you really want to. Your capability to reach iLv.100+ will be the same (or close enough to) as any other player.