That does present a pretty daunting complication to my theory! I think if he were mowing the field while they left either he could see them or the perp would believe he could see them. The only way I could see it working is if the mystery person in the truck is parked in the first position (which is not on the access road, I don't think, but farther back nearer the parking lot) until 8:45 - 8:50, waiting for the groundskeeper to leave. Then he leaves near the early portion of his estimate (8:45). A quick cell phone call to Terri as the mystery person moves the truck to the access road, and Terri exits the school with Kyron.
Possible, but that timeframe is really, really tight.
Yes STEADFAST it does make that timeframe tight but far from impossible IMO. Stensen says he stayed as late as 845-9. This to me is a guesstimation. As do I not, He more than likely isn't checking his watch continually, as most ppl don't. If he had no important appt (which it seems he did NOT otherwise I think he would have definitely said I had an appt at such&such time that morning therefor I was keeping a close eye on the exact time, therefor IMO he would have given a much more definite time of departing such as I had such&such appt and know I left the school at 850 giving me the 10 mins I needed to get to my appt).. So IMO "I stayed as late as 845-9" is definitely a guesstimation(which nothing wrong with that Id say the majority of us if having to come up with a time line the times would be guesstimated for a good portion of the times in question, except as I said above if we had certain appts at specific times therefor giving us reason to know more specific and accurate times).
So, IMO Terri left the school between 845-9(maybe a few mins earlier but not much given witness accts of times they were seen in Skyline). So, lets say Terri parks in the front of the school as her originating spot that a.m. and at 845 she tells Kyron she is going to go get the truck and pull it around for him to come out that specific door(the one nearest access rd). So Terri gets truck(add in few mins if baby K was with her and had to be buckled in)pulls around and up the access road and its now 855 and Kyron comes out the door and gets into the truck(and thanks to kimsters detailed pix upthread we see that a good portion of that exit and access road are pretty well hidden, at the very least NOT CLEARLY visible)...
So even if Stensen's time is dead on and he left at 845 that is still 10 full mins BEFORE Terri drives up the access road and Kyron exits from side door.. SO IMO yes still ENTIRELY POSSIBLE AND DOABLE!
Lastly I will add one other thing... IMO I do think that the turf tech being there that morning did offset Terri's original timing she had in mind to have the "disappearance" done and them gone. I don't think she knew he was gonna be there. IMO I think Terri had every intention of getting to the Fair, being seen, taken pix, and give Porter the appt excuse(if it took place on Fri, as its been said it was possibly told Thurs afternoon)and I think her intentions were to have Kyron outta there before EVERYONE really had gotten there. Tho JMO. However I believe that quite ironically that this offset of Terri's timing may have played in her favor(atleast as far as getting Kyron out unseen[that we know of])because IMO with all of the ppl there[students, teachers, assts, faculty, parents, siblings&grandparents]all of the hub-bub, chaos, and hecticness is exactly how they left in plain sight(Terri out the front door and Kyron out the side door)
Again alot of this is JMO but I do indeed believe it is more than possible given the times that we know of...