You're a bit upwind from Reno. Did you have monster wave conditions yesterday? We had wave with 6 visible attached cirrus cloud streets, perhaps more visible behind the mountains to the east.
So 81 hours duration from 60k ft is 12.34 fpm down, sea level landing, calm air. Probably doable with cutting-edge, maybe not a flying wing but solid 40+ L/D design. State of the art a while back was 60+ L/D. You're hauling an 80ah battery which is good for perhaps ten plus hours continuous thrust on available motors. Not enough for duration, but enough to get you into lift.
Can't see where any of this is impossible or really even difficult