And you may very well be correct, Texas Charm that it occurred at the home, but IMO for some reason I just don't believe it did.. My opinion of why he felt the need to admit to her being at the home and thereby the last to see her was due to either the logistics of it(ie. Phone records text msg possibly discussing her coming by the house that night)..or for the simple fact that he either knew or suspected that Katrina shared with someone/anyone else that she was going to Todd's house that night..
IMO its for those type reasons that Todd had no choice but to admit to Katrina being at the Tetterhall home..jmo, tho and definitely could be wrong..
As far as my theory involving Katrina's car while I find it possible, if not even probable that Katrina was in the driver seat when the attack began.. However IMO I also find it atleast possible that she was not in the drivers seat but rather in the passenger seat and Todd driving..early on one of the rumored ruses that Todd Was to have supposedly used that night in luring Katrina to the home, and then ultimately to her death..was the ruse of getting something to eat..I've looked at that possibly as his sending her to go get him take out and somehow luring her to a specific place..but IMO there are issues that I have with that in any way being a smoothly executed plan..
So, I find it possible that once Katrina came to the home that Todd talked her into spur of the moment, the two of them going to grab take out..most have heard the rumors of Katrina maybe having possibly thought of giving him another chance..but even if she didn't I still find it plausible that there relationship was still amicable enough that she would agree to go by herself to the home.. This to me leads me to believe that once there and Todd spur of the moment proposes hey let's just run thru the drive thru for some take out..your car is parked behind mine so we'll just take your car..lemme drive..it was a new car afterall..and IMO with the relationship obviously somewhat still intact on an amicable level I find it easy to believe the above given theory could have been used..jmo, tho and just a theory..
As far as your question about the where they were at location wise when the attack/murder occurred..not being local I just don't know..but IMO it wouldn't exactly be that far fetched IMO if it didn't happen at or very near the area of the river that her body was disposed of at..but again I don't know and all in all its all just theory and conjecture at this point..
The one thing I'm most certain of is that given the manner of death and disposal my honest opinion is that even tho small in stature..Todd Smith IMO quite likely did it all himself..jmo, tho.