The problem with selling privately to a prearranged individual is in gauging the real value of the house. If your neighbor wants to buy he should be prepared to pay market value and you can't be sure until you've done the research. You could always talk to a couple of agents about value, they will be anxious to get your business and should be prepared to tell you what price they would pitch it at, based on sales in your area.
But even that can be misleading. A house sold on my street the other day for at least 25% more than this time last year -- and it needs a ton of work.
And