Well,
@rahod1, that is one notion.
IF the family only intended a brief outing, as IMO, that was all they were dressed, equipped and prepared for,
here are notions that COULD explain why they instead ended up walking 6.5 miles of arduous elevation changes in upwards of 109 degree heat, with no shade from the burning sun and two vulnerable dependents.
1. They got a mile or so down the trail and, off leash,
Oski took off ahead of the family. They frantically followed his tracks down to the river and down South Fork Trail. By the time they got a hold of Oski, they decided going back via the Savage Lundy Trail was their only recourse not knowing how fragile they already were.
2. Someone had told JG or EC that they would
pick them up with their ATV below Marble Point as that friend planned to be out there anyhow, allowing the family time to enjoy the river after their 2-3 mile downhill walk that morning. But sadly, that person never picked up the family. So they opted to walk along the river and up SLT.
3. The family went off piste to explore some unmarked trail, perhaps on the other side of the river below Marble Point (if you want, poke around the SO FB page to find reference to rumored grow op locations down there) and they were
accidentally sprayed with spray trap (e.g. a poison not detectable during autopsy) and rendered incapacitated. In their stunned state, the best decision they could make was to keep going around the 'loop' perhaps unable to comprehend their grave conditions.
4. The family was the victim of a
horrendous homicide by death march, either from revenge for something (see my post ^^^) or because they came across something they were not supposed to see (perhaps they witnessed another homicide). The death march could have been orchestrated under the threat of long gun fire from a distance.
5. Somewhere along the line the family went off piste (perhaps as they headed down Hite Cove OHV Trail) and
they got lost and all turned around. They got back on the trail but by that time they were disoriented and already suffering from heat exhaustion and no longer capable of making sound decisions. So they kept to their 'loop' plan.
There is no data to support any of this. Just like, as I contend, there is insufficient data to confirm the family intended on doing that horrendous hike vastly unprepared. So back to JG's phone. If the FBI can analyze it, that phone is likely the key to either pursuing any of these notions further or simply ruling them out as fantasy. IMO.