No one stops for fuel in Aspen, sure as hell not on July 4th! $6.15/gallon.
I don't see any TFR near Vail pass, the one just Southeast of EGE has been there for weeks.
Many of us DO fly the high country regularly, it is very common around here to go to 12,500 and drive around the higher stuff, sometimes we go higher yet. But, to cross the divide is not difficult, it more more intimidating for those not familiar. Going over independence pass isn't a big deal unless you don't know what you are doing. He probably did not lean on the the ground, probably did not lean for max power takeoff, probably did not continue leaning as he climbed. If he was going non-stop to Iowa, he probably had a bunch of fuel. He was likely heavy, it was hot, and it was high. I have crossed the divide late in the afternoon, usually I don't like to as its pretty rough and frequently thunderstorms in the area.
Pure theory on my part, but here goes. The pilot was NOT familiar with high DA operations, nor mountain flying, probably loaded up fuel fuel so they didn't have to stop for fuel on the way home. I don't know what direction he took off, but typically ASE is 35. Most likely made a quick turn to head up the valley. Flying up the Roaring Fork Valley east of Aspen, it climbs fast and there are a few narrow spots, like around Green Mountain which is where Lost Man Creek comes in from the north. He probably didn't think he could get high enough to get over Indepence Pass and the valley that is Lost Man Creek looks pretty benign at the beginning. Pure guess, but maybe he thought it was a lower pass and turned that way. There is actually lots more room to maneuver if you continue up toward independence pass. The valley gets pretty wide, there is space to easily turn around. Midway pass takes you over the hill north, but does NOT get you over the divide, you would still have to cross at Hagerman pass or even further north. All of those passes are around 12k. Further speculation is that he did not hug the side of the valley to give himself room to turn around, in the middle of a somewhat narrow valley, unable to outclimb the terrain, he was out of options.