its one of those, ya just kinda set there, and awe moments, that it is finally done! and looks awesome!
i don't see any cuttings left, and i do see brown spots, and low spots were like the rotatory cutter dipped right to the ground possibly balding the ground, this late in the year, i would keep be un easy with washouts possibly happening. more so from sudden rains. and/or early spring snow melting.
if me, i might put down some straw, or like, to help deal with possible erosion control. once ya get a year or two of regular mowings, and allow the weeds/grass to grow out, to more of a yard around the house but a tad taller grass per say, vs large single clumps, erosion will most likely vanish, but until then...
i give it 2 years, with say 4 to 5 mowings a year. to help remove various weeds. and allow more of a grass to take over. i would be uneasy, trying to plant regular yard grass seed (tearing up first couple inches of dirt) due to erosion, and would more likely opt, for more frequent mowings, and long term doing. to bring things around, and keep erosion down as much as possible, if that is what you are wanting.
==============
EDIT:
for myself, the 30 or so acres of pasture, i just let it grow to weeds, 5 to 8 feet plus tall pending on location, with a couple paths through it, that are regularly mowed. lots of critters can be seen, deer, coyotes, mice, rabbits, squirrels, coons, hawks, owls, maybe some fish on a creek that runs through the pasture, lots of different smells (various plants) chives are a big one, in one area. various wild flowers throughout some hills, there are a few hills, actually i would say half of the pasture looks like your hills in some form, and of that i would say 1/4th can not be mowed (too steep), and 1/2 is running up hill along a path, and then driving down hill mowing. (to steep to drive up it (forward or reverse)),
looking at your pictures again. it is one of them *awe moments* yep yep! excellent job! i love it! alright i might have to mow down a spot on the one hill, going down from lake, (nice long hill) for sleding, now that i look at your pictures *arghs* haven't been sledding in a few years, and getting an itching!