i didn't do it because they lost all my paperwork and i didn't have time to resubmit everything, but it's a great opportunity if you're 1000% sure you're mentally ready to be away from everyone you love for 2 1/2 years. sounds harsh, but trying to be realistic here. on the flip side, when's the next time that you're going to have a chance to make such a big difference in so many people's lives? if you're up for it, do it while you can.
one of my best friends is serving as a public health volunteer in gambia right now and every email i get from her sounds more amazing than the last. to answer people's questions about being isolated, she's in a remote village a day away from the nearest volunteer, but the supervisor checks in relatively regularly (every week maybe?) and she's 2 hours bike ride from a town that's large enough to get internet, have people that speak english, etc. so it's challenging, but that's kind of the point. they do several months of training to get you ready for the cultural immersion, but there's no doubt that it'll still be tough.
if you want to do service and find the peace corps intimidating, look into americorps. contrary to popular belief, it's not just teaching inner city kids how to read. there are positions in every imaginable field in every corner of the country. for example, i work as a residential energy analyst in bellingham, washington, managed to make enough money to pay the rent, feed myself, fly home to the east coast twice, and still ski all winter long. like peace corps, you also get to defer your college loans until the end of your service, and then at the end they give you an educational grant to use as you please. obviously you don't get the thrill of going abroad, but there are plenty of people here in the US that need help, and plenty of places that will culture shock the shit out of you. if making a difference is really what your aim is (which it should be either way), americorps can be a great alternative.
my two cents.