Thought I'd mention this for users who run into the same problem I did.
In the video "Configure PPP" you guys skipped over configuring pap and went straight into chap. Don said "just when you type it, you swap out the word PAP for CHAP" indicating that the configs are the same
Well I configured my routers just like you showed in the video. CHAP worked like a charm but PAP did not. spent a good while pouring through my configs changing this and that. looked at the official Cisco documents, looked at debugs and packet captures.
It was in the cisco docs that I found out that PAP requires the username and password to be placed on the interface.
Configuring and Troubleshooting PPP Password Authentication Protocol (PAP)
"For one-way authentication, this command is only required on the called router. For two-way authentication this command is necessary on both sides."