SmartDNSProxy is what failed for me, but I'm starting to think it had more to do with trying to access MLB.TV from my Roku device. I think I read somewhere that Roku does something extra to limit your ability to DNS hop.
I'm going to try it again this year, from a laptop.
Thanks everyone.
My rep confirmed it will be a Nats Plus perk again this year.
I used SmartDNSProxy last year and it worked great. I changed the DNS setting in my router, so all devices in my house were spoofed when it came to MLB.tv. Occasionally the Roku on my TV would complain, but I could always bring the game up on either my computer or my FireTV device. Hopefully it will still work this year.