Planting in dense woods is fine as long as you have enough sunlight reaching the plant-- if they're getting a lot of shade the plants will get long and leggy. The only real way to notice them from the air is if you are planting in rows(which looks really unnatural with the rest of the landscape), or if you have a massive operation going. I don't know how many you're planning on growing but don't plant them all in one spot.
As for the deer, wire fencing is the only for sure way to keep them out. People have used urine, feces, moth balls, bars of soap too. My experience with deer in Texas has led me to believe if they're hungry enough, they'll eat your plants regardless of what is spread around them. Oh and make sure that acreage isn't an area leased out by hunters. A buddy of mine had his grow compromised by a group hunting deer a few years back.