Understand. Life is all about trade-offs. Understand though in a rural environment the odds of a development going in without city services is not likely at all. Since most of us aren't super wealthy, one has to choose how best to allocate resources. So by using more of your money for additional land to be used mainly as a buffer from others, what have you given up for that bit of assurance? Question becomes, what else could that money have been used for? So in one case, person A purchases 100 acres but really can't improve it now... but hopes to at some future time. Person B, with the same money purchases 20 acres, hires a dirt guy to remove some trees, clean up the property some and put in a pond. Then this person fences in the property and maybe starts an orchard with long lasting fruit trees, nut trees, grapes & berries.
I'm also not into partnering with anyone... especially family. Even these folks can let you down. What happens when one passes away or moves or just decides to sell their property? Unless you have spare money to buy it, you just might still end up with someone you don't like right next to you. Also, even 100 acres really isn't all that big & doesn't buy much isolation. You will have neighbors no matter what. My experience is rural neighbors are all just good folk. As a group, I think much better than city folk. I like having friends and neighbors close by. In my case, due to the layout of my 20 acres, our house is on the crest of a hill within 200' of one neighbor. On the other parts of my property you could go miles without reaching a neighbor. That is just how land sometimes works... you don't always build your impregnable castle dead center of your estate.
I understand preppers aren't trusting souls but sometimes (most times) the best strategy is to build friendships with your neighbors. Help each other with projects and mutual security during normal times. Lend each other tools and occasional manpower. I have found this is not so easy in an urban environment but completely natural in a rural one. So my suggestion is not to fear neighbors but to cultivate them as you would a crop. Spend time with them, help them when it is needed. Worship with them and maybe root on their kids at sports events. Guess I look at it different than most here. I see neighbors ( a few, not a whole subdivision) as a resource in a rural environment... not a liability.