i agree an angle is better but takes more excavating and work due to the offset in side hill berm required. you may also have to put in a diagonal drain depending on the slop length to carry the water under/out of the road bed or alongside if you can engineer that during the construction.
The raised road bed is good however around here if you do it like that, ( i made that mistake ) the top soil will wash/sink and water runs down the tracks and washed the road out over and over and you have to keep rebuilding it, so i had to learn the get all the topsoil out of the way and then get to teh clay and build the raised road with it, then put 3 to 4 inch gravel on it to support weight and use the topsoil for dressing what you tore up getting the clay dug up. So many ways to do this depending on what you want to accomplish and get to in that one acre. if you only intend to take the tractor up there thats one thing but if you intend on using it for recreation and having a truck back there something more substantial will be required - like jeff said depends a lot on rainfall, grade, dirt, etc.....but just from the looks of your beautiful picture, its lush there, you had lots of loose pine needles to deal with too with love to float/wash and are not very stable - heck if its just the tractor going up/down i wouldnt get too carried away you will get a path beat/worn down eventually that will work/serve for the few times you will need to mow/manage the area