I second that two guinea pigs are better then one. Guinea pigs are very social creatures and need a lot of attention and companionship. When you start back at work he'll be alone all day and that's not really fair to the pig.

As long as you have a decent size cage (www.cavycages.com) and you clean it regulary there is no smell to worry about. Although males do have a musky scent they are known to release.