netcfg doesn't show a ppp interface type when attempting to add an interface on a new install of pinstripe. It seems to call rp3-config if I create enough of an interface (/etc/sysconfig/network-scripts/ifcfg-ppp0) for it to edit. rp3-config is also broken from what I can tell.
This is correct. Getting netcfg, linuxconf, and rp3 to interoperate in terms of setting up and modifying PPP interfaces is nigh-impossible, so we're centralizing on rp3. If you're having problems with rp3, please report them.