As a few others have said, there are just a few things that do not add up here.
1.) If WH left at 6:45am to get to work before 7:00am, where did he supposedly ask her to give him a ride to exactly that would take so little time, she could still arrive to work before 7 and if it was that short of a distance, why would he need a ride in the first place?
2.) If JH waited 5 minutes after 6:45am to pull the gun on her and forced her to go straight to Roslyn Lake to force her to perform oral sex on him, how is it possible that he killed her then showed up at gas stations NORTH of where the lake was at a later time in the morning? It is only 14 miles from their apartment complex (Heatherwood Apartments) to the address listed on the probable cause document. Here is a map showing the driving directions from the apartments to the lake where he supposedly did the deed:
http://goo.gl/maps/a9ZB2
And here is another map showing where the items were located throughout the areas north of the apartments:
http://i.dailymail.co.uk/i/pix/2012/10/22/article-2221422-1594F5E7000005DC-644_634x416.jpg
Based on where they found her cell phone and her vehicle north of Gresham, and he really did force her to drive them to the lake right around 7:00-7:15am that morning, it would seem that he committed the crimes at the lake, dumps his cell phone there, goes back north and stops at the gas station at 9:14am when her card was used (was WH still in the vehicle at that time, after he shot her?), drove to the mountain to dump the body (while also dumping the license plate), then on his way back, threw her cell phone out into some bushes while driving the SUV shortly before finally stopping at the WalMart to dump the vehicle.
3.) If JH shot WH after the sexual abuse, it is not clear how the police have not found a single drop of blood either in the vehicle or at the location JH told LE he committed the murder. Not only that, but how could he transport her bleeding body after 4 gunshot wounds all the way to the mountain without any blood getting anywhere in the car? He brought plastic bags or a blanket or cover or something with him? If so, how would that not have seemed very suspicious to WH when he asked for a ride?
None of this is adding up to what JH told LE. It seems there are just too many details missing right now for any sort of conclusive findings.