I live in Clarksburg and am very familiar with the community. Are you looking to buy new construction or resale? A realtor is definitely necessary for a resale, regardless of your financing source. The agent can handle the negotiation (price and terms), the inspections, coordinates the title work, etc on your behalf.
If you are buying new construction with the builder, a realtor is helpful, but our help is limited as the builders rep does alot of the job. Also, if you've already been to the model and talked to a sale rep, most builders will not honor a realtor.