I know I might get flamed for this
The best way to find out is search the forum. Ghosting PBNs is kinda bread and butter for BH SEOs now so you'll find everything you need.
The main areas to worry about are:
1. Making sure you spread out your PBN across IP addresses. Class 3 and stuff like that is not good enough, just setup accounts on multiple cheap shared hosts.
2. Make sure you're not using the same WordPress themes and styles. Try to make each site look like it's been designed in a totally different way.
3. Block bot using .htaccess (There are posts on here about that) don't bother using robots.txt because it's a footprint in itself.
4.Use fake whois info, don't simply block your whois data. Try to keep addresses and names different on each domain. Managing the email addresses and stuff can be hard, it's a good idea to break out Excel or Open Office and keep a spreadsheet of everything because you will forget!!!
Do plenty of reading on this forum, understand the technical aspects of what you're trying to achieve and then have a plan to secure everything up you can roll out across your network nice and easy.
Btw blocking all IPs except Google from visiting your site is the oldest trick in the BH book. It was called cloaking back in the day and isn't worth the risk. By using WordPress, keeping it updated and taking care of the security aspect you'll be good to go. The ideal scenario is that all your PBN sites look official anyway so when competitors look they don't see anything weird anyway.
The most important security aspect is the one nobody talks about either! The human factor! Don't tell a soul about your network, keep your spreadsheets secured on your own PC and keep everything to yourself. Loose lips sink ships!!!