I want to learn wireless network penetration testing and need advice on setting up a proper home lab. I'm starting from scratch and want to do this safely and legally on my own equipment.

My current plan: I'm thinking of buying a cheap TP-Link TL-WR841N router (around £15-20) and an Alfa AWUS036NHA WiFi adapter (around £20-25). The idea is to keep the router completely isolated - no internet connection, just a standalone test network that I can practice on without any risk to other networks.

What I want to learn: Network reconnaissance, capturing handshakes, testing different attack methods, password cracking, and implementing defenses. Basically understanding how these attacks work and how to protect against them.

My questions:

Is this router adequate for learning, or should I invest in something better? Will keeping it offline and isolated be enough to ensure I'm not accidentally interfering with neighbors' networks? Does the Alfa adapter work well with Kali Linux in VirtualBox, or do I need to dual boot? Should I have a second device (like an old phone) connected to the router to simulate realistic scenarios?