I've been on the road since June of 2008. Gradually less campgrounds and more boondocking. I like my privacy and try to park as far from other RVs as I can.
As a single female RVer I came up with a trick that has worked for me. I make a big batch of homemade cookies and only partly bake them. Then I freeze them - six to a package. When I arrive at a new boondock location, before I begin to set up camp, out come the cookies, into the oven for 5 minutes, and I bring a plate of fresh homemade cookies to my closest RV neighbor within 10 or 15 minutes of my arrival.
They're usually astounded at how fast I could do this and that's where the conversation starts. If they were wondering why I'm approaching them, seeing the plate of cookies has already put them at ease.
I'm able to meet my neighbors and quickly size them up. I always have a story prepared so that if something doesn't feel quite right, I will tell them that I've only stopped to have a snack and check this place out for another time but I can't stay tonight because I have to move on to meet up with a friend. I've not had a reason to use that story yet.
I'm usually pretty comfortable asking if we could keep an eye out for each other after we chat for a bit. Sometimes I don't even tell them immediately that I'm traveling alone. They can figure that out for themselves.
I've made more friends with my "boondock cookies" than I have in the pay campgounds where I am a good neighbor but mostly keep to myself.