Good work so far. I'd closely inspect the big tree at the property/fence corner. Can't see it well enough, but it looks to be greatly imbalanced with all leaders going in toward property - maybe due to overhead power lines? Look for rot in the crotches and any insect damage. Cut out whatever is bad or lighten the lean by removing one or more leaders. JMHO, as a former tree surgeon....
You are absolutely right. This area is a fairly continuous slope downward to the west. Luckily I am on the higher side ( my neighbor ALWAYS has standing water in his pasture ) The area where that massive tree is has another pretty significant dropoff; however I think on that side Ill need to bring in some dirt and even it up because it is probably a 3' or greater elevation difference.