NOTE: I've updated what I've done below in the comments. I will update if there are any more issues in the coming days.
The phone is Virgin Mobile's EVO-V (rebranded EVO 3D) which Virgin's stock ROM. The phone is rooted.
I followed the instructions here: https://help.ting.com/entries/21798151-samsung-m370-donor-phone-getting-the-aaa-shared-and-ha-shared-passwords
I can make voice calls and get 1X data. I haven't tried texting since I do that through Google Voice.
Initially it looks like my phone gets 3G (shows 3G icon) but data connection is really sporadic (connection problems). I also tried pushing the 61087 PRL found here: https://help.ting.com/entries/21650626-flashing-16-byte-aaa-key-over-to-sprint-optimus-s-3g-problem. After that it was about the same. It was roughly the same but I was also getting a lot of error 67 messages (including when trying to OTA update profile/PRL). While looking into that I found a way to go through activation again, get profile, and update PRL and then I only ever get 1X data, but it's reliable.
I used CDMA Workshop to write the Profile 0 and Profile 1 HA/AAA keys. Looking at the EVDO Engineering screen it looks like I'm connected, the AA status says 1 Authenticated. Do I have to write those keys for the NAM1 and NAM2 profiles? I wrote them while picking the NAM1 and NAM2 in the pick boxes while EVDO is also in the other pick box. It looks like those keys are independent of those profiles.
I read elsewhere online that you need to set the active profile to 0 which I do and after reboot it reverts to 1 which I've also read is normal.