Chris D did some quick math to see the cost of putting topsoil over the gravel. An assumption is that topsoil over gravel will provide an adequate environment for growing grass. The below prices come from Bellingers, who can be reached at 585 728-3906.
Area of property=29,00 sf
Area to be covered with topsoil = 10,000 sf
Volume of 1″ over 10,00 sf =31 cubic yards
Cost per cubic yard delivered $41
Total cost for 1″ coverage spread by hand= $1,271
Total cost for 3″ coverage spread by hand= $3,813
Belligers sells topsoil by the ton. A 21 ton load, which is about 14 cubic yards, cost $575.