Okay, I bought my wife a new tablet (Asus 10.1") and I am finally at the point where I am ready to give this a try.
Just to recap, I am running software version 7.4.8_user_4849020, TWRP 220.127.116.11.
Can I just flash TWRP 18.104.22.168 from TWRP 2.6.3 and then flash CM 11 from TWRP 22.214.171.124? I was able to do that with my Asus tablet without any issues. Or do I have to go back through using fastboot.