Once I've got my recent VFF-triggered heel pain resolved, I'm going to steadily build up to being able to walk 12 miles in them--about the pace of walking across England in 15 days. Should be able to do that nice and slowly since it's years till I'll do the actual coast to coast.
Does sound like on a multi-day hike, it would be worth having a spare pair of regular hiking boots just in case feet get sore. Luckily, there's a sherpa van service that drives baggage from one overnight accommodation to the next (no, I'll NEVER be primal enough to hike and then sleep in a tent )
Zone diet on and off for several years....worked, but too much focus on exact meal composition
Primal since July 2010...skinniest I've ever been and the least stressed about food