For your purposes, I recommend @Laravel, or even @Symfony or @Yii, or whatever. In your use case, a framework is 100% indicated, because it will cut your boilerplate in half or more, and you'll have a pre-fab organization for files, classes and so on. Personally, I am not a fan of Frameworks, because they tend to take over your project like cancer and trap you. But for an internal app to manage stuff, it's probably the best idea to use one (preferably one you like).
When doing internal apps, your best bet is to stick the essentials and basics, try Laravel with MySQL on a nice Debian virtual machine. Can't go wrong.