It's not uncommon for the neophyte to look at the mass of choices and just shut down (autocorrect thought "mass" should be "mess". It feels the same way.) A few thoughts to take the edge off.
First, you don't want to be everywhere. Start with a manageable piece and grow.
Also, there is no reason this should take hours...until you have a large audience. Even then, most engagement can take just a few minutes at a time. Utilize your DMV wait to reply to Tweets, check in with LinkedIn contacts or Facebook chums. Combined with a mobile device/smartphone, you can fill in those old "boredom productivity gaps".
See, social media really isn't as horrible a time-suck as rumored.