Pyro isn't a big deal to tackle. If you go with the times/temps of the Massive Dev Chart, you'll be close enough for horseshoes, hand grenades and government work. Typically, you rate film developed in Pyro developers about 1 stop slower than manufacturer recommended ISO - so in other words, best results from FP4+ are obtained at ISO 64, not 125. HP5+ is about 200, and so on.
Why won't you have access to Pyro? all it takes is $25 and a phonecall to Photographers Formulary or B&H. Get Pyrocat HD - trust me, it's cheap, lasts forever, and you won't regret it, especially when doing alt process printing. I'd say go for platinum/palladium if you want to alt print your 12x20s. You can still coax good prints with silver papers out of the negs you make for pt/pd if you use VC paper, and print around grade 1/2 to grade 1. If you go for some of the other alt processes, like albumen, not only is the learning curve steeper, but so is the density curve on your film, and they'll be unprintable in another medium.