I have never thought her murder was planned, but rather was the result of a temper gone berserk. I do think Condit lied to her and set up a meeting for the afternoon of the 30th, in which he thought he could promise her anything, and get her out of DC back to CA, and she would wait for him to contact her. He may even have promised her a romantic trip as a reward for being a good girl. But Chandra wasn't playing anymore, too much had happened to her in one week and she was insisting on a committment from him and a time line. No doubt Carolyn's presence in his condo make Chandra jealous, and jealous women do not act with prudence.
I suspect he picked her up in his little red car, drove her to a secluded place (klingle Mansion?) had sex, a fight and choked her to death. He then drove around looking for a place to leave her. He didn't have a lot of time and driving around with a body in the front or back seat wasn''t smart. At the top of the hill he made his decision.
In order to get her out of the car, toss her down the hill he tied her arms together with the only thing available to him,(she was probably wearing the other articls of clothing found) making it easier to move her. He would have been panicked, but he was also lucky, no one saw him. He tossed her walkman and anything else she had with her down the hill after her, taking anything he thought would help identify her, ring, keys. He then went about his life, rid of her. The trip to Luray VA could have been to dispose of these items.Hiding them would have not been a problem, as had time on his side.
She was not near any path, and people did not regularly go where he dumped her. Time was, he figured on his side. I do not think he had help, as that would put him in the untenable situation of being controlled by someone else. He did however get Mike to lie for him more than once and may have paid him to do so. After all, Mike adored him.(?) Mike also helped him dump the watch box, but Joline had been Mike's girlfriend and he may have been protecting her involvement, not protecting Condit..
I do not think anyone has any sure knowledge about this, nor was he seen by anyone that afternoon, who until now would have known what they saw. I may be totally wong about this, but he is the only suspect with any reason to get rid of her and self absorbed enough to do this unthinkable thing. Just my thoughts.