Try planting lavender, mint, and chamomille around your crop...these herbs have been known to neutrilize the smell of your plants.
Honestly I don't think that's a bad idea. If your worried about the smell, you could collect a few road kill skunks, triple bag them- air tight, and put them in a spare freezer till flowering time. Then throw one in front of your neighbors house every few weeks. Pretty disgusting though- not doubt it would be a good cover.
How close to the plants will you have to be to smell them if the wind isn't blowing on an average temp day, say 68 degrees
Well it really all depends where your at in the season. If your a week from harvest chances are its gunna fuckin smell pretty strong. the best thing i could suggest is try to find a place thats up high, like the top of a mountian. I grew in a tree once. Climbed to the top and cut it off. Built a little railing around it so the plant pot wouldnt fall over, then ran a hose up the tree connected to a bike pump to water it. You could feel when all the air was pumped out of the hose and when you were pumping water. Couple of good pumps and presto. your growing weed in a tree!!!!