I've found that the administrative details are pretty minimal when you do your filtering well- people on Elance are often looking for long-term gigs, 10 hours a week, 5 hours a week, that kind of thing. That incentivizes them to work with you with an eye to the future, so there aren't as many details to the day to day.

The trick really is in getting rid of 99% of the applicants, and then paying well and being nice to the person you choose.