Access: While few in number, there are still some properties that don’t have legal access – that is, a deeded access-easement, or frontage on a public road.  This is what is known as “landlocked” property, and it is of considerably less value.  If you see an extremely low-priced piece of land for sale, it may be a bargain, or it may just not have legal access.  Curing this can be fairly simple, but don’t count on it.  If it were an easy matter, it would likely already have been fixed.  In most cases, legal access will require a deed from the neighbor whose land you’re crossing, and folks tend not to like to sign deeds unless they get something of significant value in return.
You can also look to certain companies and organizations that have a concentration of people that may fall in the above mentioned roles such as investment companies (i.e. Charles Schwab, Fidelity), financial advising companies (i.e. Morgan Stanley, Merrill Lynch). There may be a higher concentration of people who can both afford and want to build their own custom homes or to build income-producing properties. Try linking yourself to financial advisors who may already know of people who have these types of dreams. This isn't a comprehensive answer of all the possibilities but just some thoughts. Good luck!