From reading the directions it doesn't seem to difficult. I have my extra t's and 120 ohm and extended cable. I will run my cable from the front unit to the back. Hook up the t's in bus and hook my cables to the bus from the console unit and puck. Am I thinking right?

Sounds like you're on the right track. I just had 2 520s installed and linked. You'll also need one male and one female termination for the end of the network. The Lowrance website has a system builder where you can build your system how you want it, tells you whether or not it would work as built and recommend additional parts needed to make it work, and it will also print you out a parts list for everything you need for your specific system.

I just networked my 522 and 520. It was actually pretty easy. I put the "spine" (tees and terminal ends)under the console and ran all the leads out from there. I put a 522 on the bow so I only used one 20 ft extension lead since the antenna is internal.