Selecting the right property

Hello, I am new to this site & relatively new to permaculture in general. The extent of my knowledge has been a variety of podcasts, youtube videos, & poking around this Web site.
I wasn't really sure which forum to post this in so here it goes...I can move it if someone has a better suggestion.

I currently live near Omaha, Nebraska in a housing sub division on 1/5 of an acre & my family is looking to make an escape to a more rural setting.
I have watched Geoff Lawton's video on a permaculture property checklist but I have had trouble finding a lot of resources regarding transforming a previously mono-cropped property into a food forest.
A friend of mine is in the process of purchasing a 30 ish acre parcel that was most recently a corn field. If she can, she plans to sub divide the property into 5+- acres for her house, 20+- acres for orchards/etc, & it would leave between 5-8 acres available for sale.
I plan on taking some online design courses before I get too far into the process, but I will likely have to make a decision about purchasing this prior to having that opportunity.

So I am looking to the experts for some advice.

The property is within 30 miles of Omaha. I am assuming that it has been sprayed with chemicals in a conventional farming practice. The land that would be for sale is a triangle shape that is partially flat but most of it slopes to the east towards a timber line that seperate it from the adjacent property.
My main concerns are...(not in order)

1. Residual chemicals in the soil

2. Being surrounded on 3 sides by mono cropped properties/more chemicals

3. How much slope is too much? I haven't measured the degree of slope yet but I will. I realize that slope can be a great asset but at what point does it become more work than benefit in a permaculture system?

4.What would be the ideal slope direction in zone 5b?

This property would be great from my perspective of living there...just not sure as far as the permaculture aspect.

A little more info I forgot...I plan on buying some land & equipment in 2016, maybe a bobcat &/Or back hoe...
I plan on eventually building a house on this land within 1-5 years after buying & begining development & I will live in my current house (20-45 minutes away depending) until that time.

Thanks in advance for any input...I appreciate it.

My big fat opinions :

1. Residual chemicals in the soil

I think these will disappear quickly as you improve the soil with a lot of support plants (Geoff Lawton uses 90% support plants initially in food forests) and get a lot of fungal activity by putting woody material on the soil.

2. Being surrounded on 3 sides by mono cropped properties/more chemicals

Herbicide spray drift may be a problem on the edges of your property. You might want to have wide sacrificial borders of fast-growing plants which could be your Zone 5 with lots of tough native plants.

3. How much slope is too much? I haven't measured the degree of slope yet but I will. I realize that slope can be a great asset but at what point does it become more work than benefit in a permaculture system?

If you want to graze animals you'll need to be careful if the slope approaches 10%. Cattle don't like to graze on such steep slopes, apparently. Also there can be serious erosion problems. Not a problem with food forests, though.

4.What would be the ideal slope direction in zone 5b?

South

Thank you for the responses Tyler!

I found a few more pics of the property to share.

The general direction of the slope is facing east although there are portions that face south & a smaller area that faces north.

The small water way appears to be just past the property line..shucks...the pic was also after a fairly large rain so it may be dry during the summer months... I would imagine that I through the use of swales & dams I could capture a lot of this before it exits the property.

Usually commercial corn fields are sprayed more with insecticides (pesticides) than with Herbicides, this makes it not so hard to use mycorrhizal fungi to clean up the residue left behind.

Any time you are going to remediate previously commercially farmed land you want to add as many fungi varieties as you can, the best ones are the local varieties you would find these mostly in that tree line along the property line.
When there is active farmed land next to you drift is the big issue, planting a double or even triple tree line of fast growing, thickly branching trees will help in keeping that spray drift out of your property.
If the adjoining farmer uses air delivery spray, you would want to have a nice discussion with them, the goal is to get them to either use a different method or see if the plane could change the direction of the passes so the drift is minimized, this may or may not work but is always worth the effort.

Tyler has addressed the probable issues well.

I would look at the land several times, decide on the home site and stake that out before doing anything else.
Keep in mind any flooding that has occurred over the past 100 years when you are planning the home site, you want to be on high ground.
Now you know where you will live and can plan your zones from there.

The slope in the photo 20151214_154854.jpg looks like a great place to put a food forest.