How to Retrieve SD Card Files via fastboot or recovery?

I have a Nexus 4 (LG E960) running rooted stock 4.2.2/JDQ39. The phone fell from a foot high and the screen cracked. The touchscreen no longer works. I have a full Nandroid (TWRP type) backup under /storage/emulated/0/TWRP which I want to retrieve to install in the replacement phone. I can connect via fastboot but I cannot connect via ADB (neither via Command-line OR Wug's Nexus Root Toolkit). ClockWorkMod v6.0.2.3 does not give the option to mount USB storage. **I need to retrieve those files. I need to either connect via ADB (in recovery or use fastboot to enable ADB in booted up mode) OR mount USB storage. What are my options?** PS: This thread on XDA Dev does not help in my case as I do not want to erase my phone.