I live on 80 acres and it doesn't surprise me in the least. I pay no attention to my neighbors comings and goings and to be honest, if they came to my door I'm not sure I would even know who they were by sight. I don't even know what they look like. LOL I do have their phone number and I have talked to them on the phone numerous times regarding missing and/or found dogs and cats, but we just don't ever see each other. Also, people use those shipping containers as storage quite often. I wouldn't think much if someone had one on their farm.
People on farms all have tractors and sometimes other equipment (we personally have bulldozers, backhoe and track loader) so none of that would raise any alarm either. We often burn brush piles (if you have land, you're going to have a brush pile...it's a fact of life) Also, I don't even bat an eye if I hear gunshots, as someone is always target shooting and then during deer season, there will be hunters shooting within hearing range. It doesn't even register in my brain it's so common.
Now, all of that being said......I would have found it weird and very odd that the man had a large tract of land such as that and he had it fenced with a 6 ft. chain link fence. I would have found that VERY odd. The only reason anyone in the country has a fence like that is if they keep deer or some other type of wild game in a preserve type situation. I saw he stated on facebook that he did that so his dogs could run, but that doesn't make much sense to country folks. But, naturally the first thing that would come to mind is that he's just a city boy that doesn't know any better, not that he's keeping hostages on his property. It would be weird, but not weird enough to really raise any suspicions.