I don't have the quote, but yesterday, I believe Molly said something about and article on Condit mentioning how he liked to ride his bicycle through this park in between sessions in Congress.
It appears to me that Condit knew that park a lot better than Chandra did. He might well have known what areas were especially likely to be deserted and when. If Chandra had been very familiar with the park, she would not have looked it up on her computer for location, IMHO.
I believe he lured here there with the promise of a fancy picknik basket from a caterer and a bottle of wine for a cozy afternoon before she left for CA. He may or may not have sent someone else to pick her up, and it may or may not have been him she ended up meeting in the park. But I believe he set up the murder to get her out of his hair. Whether he, himself, actually carried it out is a tossup, to me.