I thank everyone who has responded and appreciate your concerns and suggestions.
Let me add that with someone on site it would deter the trespassers. The one site I used as an example is a worse case scenario. As I see it, the biggest problem at this site is there's no locked gate. On the internet I found many blog posts where several folks had visited the site and indicated that even though there were federal land "No Trespassing" signs, since there was no locked gate they decided to drive in and look around.
Most of the sites are completely fenced and gated which would offer good security for a care taker.
Communications usually isn't a problem since these sites are on mountain or hill tops along with cell towers from most providers.
Based on the comments so far, when I present this idea I will include the possible need for full hookups with at least 30amp electric.
Thanks again for your feedback.