Aloha.

How big is an "area"? Outdoor plants will fill all the space given. Why plant 5 when 3 (or less) will produce the same amount? Two KM,s is not that far. Sounds like you will be visiting way too often. How will you minimize your trail? In my outdoor grows I will put them in a line of 2 or three plants with at least 100 ft seperation between patches. The more scattered they are if a rip off gets into your stuff he may miss a few.

Hawaii has very rich soil so when I go out, I take plants. Time release ferts. Digging tool. And a single crushed up water container. You don't have to prepare the soil much. But the more sun the better the plant grows. If you want to cover your bases go out before planting, pick your spots, check all your sight lines and sunlight. Get to know your area.

Three ft between plants is ok. Ten ft is better. You may have to tie a monster down.

Security is up to you. I work under the rule, if they can find them I screwed up and do not make the same mistake twice. Your best defence is not to leave any trail. Watch the mud on your boots. Don't step on branches or fallen trees. If possible make a hole and go under things in your way. If there are thorny plants around use them.