I still like the theory that the money was buried at Tena Bar shortly after the jump and was then infected with the diatoms when the Columbia flooded the following spring.
As far as what happened next, it's a "choose your own adventure" story. Maybe Cooper goes back and retrieves the money while accidentally leaving 3 packets behind. Maybe the flood water washes the money away while 3 packets somehow get left behind and Cooper never does find anything upon his return. Maybe the money was not buried there by Cooper but by someone who was in the right place at the right time and found some bundles of cash (or an entire bag of cash) in the woods in the days or weeks after the jump and buried it because they knew what they had found and were understandably a bit paranoid.
Regardless ........
Even with the western flight path, Cooper is not landing on or near Tena Bar. If we're accounting for the northeast wind pushing the placard east, then we have to account for the same wind also pushing a parachuting Cooper east. And even with a flight path that is directly over Tena Bar, Cooper is touching down east of Highway 501 (NW Lower River Road) and likely east of the Lake River as well.
If he begins walking west after landing, he would encounter the Lake River. It's hard to see him crossing that -- in winter and possibly at night -- unless he gets lucky and finds a nearby bridge. Best I can tell, that river is a good 200 feet wide even at it's most narrow point.
He would then have to cross 501 to reach Tena Bar. It seems much more logical that when he reached 501, he would follow it and not just cross over it. After all, the goal is to get out of the wilderness, not further into it. Following the road is a way out. Crossing over it is a way back in.
So the idea of Cooper burying the money at Tena Bar requires him to cross the Lake River and then cross 501, both of which seem like odd things to do. Now granted, Tena Bar is only around 500 feet from Highway 501, and if he were looking for a place to stash money, he may have felt safer (less likely to be seen) doing it at Tena Bar as opposed to next to the road where a passing car might see him. And Tena Bar provides an easy landmark / reference point for him to retrieve it later on.
Further north, the Lake River gets further east of the Columbia, so there's a little more room for him to come down in between the Columbia and the Lake River. And if he finds the Columbia and follows it south, he could arrive at Tena Bar. But that would require crossing over waterways in at least 2-3 different places in order to get to Tena Bar. One (that connects Post Office Lake to the Columbia) looks rather innocent. But another (that connects Campbell Lake to the Columbia) looks a bit more daunting at around 60 feet or so in width. And just north of that is another of similar width.
Again, it seems unlikely that he would be crossing rivers and streams given the circumstances. But I will certainly concede that the notion that he had to take certain risks to get away one way or another.
Bottom line .... the diatom evidence is great, and it helps make a strong argument for the money getting to Tena Bar by human intervention before being exposed to the diatoms the following spring. I just have a hard time getting Cooper from his landing spot to Tena Bar.
I like this post. Finally, someone recognizes the importance of analyzing the location of Tena Bar relative to other places. More to the point, that it is effectively on an island, and therefore, creates a set of hurdles that need to be explained. Well done!
Now let me discuss some of the statements above.
I believe that DBC jumped very near the 8:12 time stamp. Additionally, I believe the jet flew the Western Flight Path as I've described many times. This puts DBC's jump point over the northern end of the Ridgefield National Wildlife Refuge--just south of Woodland and the Lewis River.
After jumping, DBC would have drifted some distance to the northeast. Considering this, I believe he landed on the other side of Lake River--that is to say, on the same side as the railroad tracks.
I believe this means that DBC most likely landed in or very near the Carty Unit of the Ridgefield National Wildlife Refuge.
I believe upon landing DBC stashed his parachute along with the dummy reserve that he used to hold some of the ransom.
DBC then would have started to walk south--toward Vancouver. And, in my mind, the railroad tracks make an ideal corridor.
A little south of the town of Ridgefield, DBC would have crossed Lake River--via the only crossing point--utilizing the River "S" Bridge. From there it is merely a matter of walking south on the only road out--Lower River Road--which ultimately brings him right by Tena Bar.
Now DBC, recognizing that he cannot walk into town lugging a 20 pound bag of cash, smartly opts to walk over to the easy-to-dig sandy beach of what is Tena Bar and temporarily buries the ransom. Yes, he digs a hole, lays the white bank bag in it and places the loose packets of twenties--from the dummy reserve--into the hole as well. He then covers the stash and continues south to civilization.
After this, my "Spring Retrieval Theory" picks up.