What is the difference in degrees between an actual temperature of 35 degrees and that temperature combined with a wind speed of 40 mph

A negligible difference. Wind speed of 40 mph generally does not change the temperature of the air that much.

However, I believe you are meaning to ask what the difference feels like if you were subject to these conditions, this is a more complex answer. (Assuming that your skin temperature is greater than 35 degrees) You first need to understand that a change in wind speed would only decrease the time taken for your skin to equalise it's temperature to the surrounding air and thus feel 'colder', this is because more air is flowing over your skin per unit of time.
There are multiple other factors in determining what the 'feels like' temperature would be, such as taking into account the humidity and density of the air combined with our understanding of how heat is lost from the human body.

River valleys were good places for hunting and fishing.