J pike,
Everyone pretty well answered your questions, except for the pH. 4.9 is getting very low. From my limited knowledge, I would say that it will grow. For grasses (like rye,wheat and oats), pH is not as critical as it is for legumes. The advantage of having a pH near 7 with grasses, is that any fertilizer that is applied will be more available for the plants to utilize. So you will get more bang for your fertilizer buck if you bring the pH up higher with lime which is generally cheaper.

I would also disc before planting if time and terrain permits it. Depending on what I plant, I generally just lightly disc after seeding. This works well with rye, oats and wheat where planting depth is not as critical as it would be for clover. Like someone said above, you can just top seed grains on bare ground, but the birds and the weather will play a major role on its successs. If there is a major vegetation growing on these roads, success will be reduced. Shade may have some factor on the logging roads as well. Good luck.

greg