D1 gravel for road

7000 feet long 30' wide with 6"D1

7000' x 30' x 6" = 1,260,000 ( cubic inches? or cubic FT ?)

It's neither cubic feet or cubic inches, but a mix. An easy way to obtain cubic feet is to let all factors be in feet. To convert inches to decimal feet, divide inches by 12, e.g., 6 inches / 12 = 0.5 feet.

So: 7000' * 30' * 0.5' = 105,000 cf (cubic feet)

Do I divide or multiply by 12 to get cubic FT? and then divide or multiply by 27 to get CY then multiply or divide by 1.6 ( coefficent for D1 of tons per CY) to equal tons?????

To obtain cubic yards from cubic feet, divide cubic feet by 27, so: 105,000 cubic feet / 27 = 3,888.89 cubic yards.

You have a volume to weight factor (D1) of 1.6, so: 3,888.89 cubic yards * 1.6 = 6,222.22 tons