Replying to i just got a road bike for free...

my friend had this old road bike he wasn't using and offered it to me. i hopped on the opportunity and now have this decent bike for some fun. i'm not real knowledgable with bikes, so i'm looking for some opinions that know what they're talking about. the frame is light and looks to be in good condition, same with the handles and all that bumbo jumbo. i think it may need new brakes, if so, i'm thinking all i want is a rear brake. would i ever be in a situation where i'd need a front brake, too? i pretty much only use a rear brake when i ride bikes. i also want a nice seat so that my ride will always be comfortable. do they make grips for the handles? i'm pretty sure the tubes are pooped, so i plan on picking up some new tires and tubes. i may possibly need a new chain, but i may be able to get away with greasing the current one. any suggestions? tips?