40 miles is a long way from home if you were on foot. If I were to draw separate lines to N/S/W/E compass points 40 miles out in my AO, I would not be looking forward to a walk of this distance.

I can walk 5-1/2 miles in just over an hour (70 minutes) on pavement/good terrain with good proper shoes (not dress style) however I could not keep this pace up more then 2, maybe 3 hours tops on a good day without fatigue setting in and my speed dropping substantially. If your pace drops down to 3 miles an hour, do the math and you will see that a 30 mile walk can be 10 hours for more. Also keep in mind, even walking requires regular training. There is a local walking charity event here that is 30 kms (18 miles) in length and every year hundreds of "fit" people drop out due to sore feet / ankles, sore shin muscles etc.

I really suggest the maps and only the carry the essential, meaning cutting the map(s) to include your possible routes only. Alternatively save some offline Google Maps to your iPhone as every block or 1/4 mile saved by shortcutting through parks, shopping complexes etc can make a big difference when your hoofing it.