I would think it would take more than 800 acres of corn and beans to justify full time help, even if you bought a truck and had the employee deliver the grain to a market 40 miles away.  I'd lean towards some seasonal help as needed during the spring and fall.  Make the job as simple and easy as possible so that most anyone available off the street can do it.  Most of those available will have some sort of limitations.  I'd rather deal an employee with some limitations that I otherwise trust than a more capable employee that I do not trust.  If they are only working for a few hours during the busy season, you can afford to pay them a generous hourly rate without hurting the bottom line too much.  You can maybe use a combination of part time workers.  Some with full time jobs in town like to get out and do some farm work during their off hours.  Some others get tired after a few hours and need a break.  I'd rather have two or three running shorter hours than one working longer hours, getting tired, risking accidents, and getting burned out.  If you can work full time, just a few thousand dollars per year should get you all the help you need unless there is more to be done than I am seeing here. 

Edit:  I did not read the other responses, but make sure your insurance covers the employees.  You might need to get workman's comp coverage.  Employees or other people in general have a way of doing things you've never dreamed of.  It's mostly harmless and sometimes an improvement, but make sure you are covered just in case.  There could allso be some extra tax forms to file, but you are probably aware of that.