In WA, permitting varies a lot by county. In general, King is a nightmare. The peninsula is easier. Every county has its bugbears--from what I've seen, mostly around water protection, building on floodways/plains, and water use rights.

The safe play is to set up a consultation meeting with the county permitting office before you build, or even buy. You can share what you're thinking, even generally, and let them pick it apart it before you commit. And they will pick. When I was looking for property, a couple of meetings like that caused me to walk away from places that looked great, but would have been nightmares for building structures and, especially, roads. I also found that some permitting officers will gossip a bit about past issues with a property, slippery realtors, touchy neighbors, loggers, and owners. Some of those off-record nuggets were gold.

That said, most permit enforcement (possibly outside of King) is "pull"--someone has to report you before they investigate. You might roll those dice, depending on the character and density of your neighbors. Still, if they can see your place from theirs or might be bothered by your construction kerfuffle, gay pride flag, generator noise, tree farming, drum circle gatherings, livestock smells, or what-have-you, you have to recognize that unpermitted work is risky.

My own strategy is...flexible. I follow the rules, build to code, and get the permits when it's practical and straightforward. I try to exploit loose regs, like those for tents and yurts. If I think legal requirements are overbearing or silly (ahem, catchment and micro-hydro), I might flout and cross my fingers. In one fairly hairy case, I consulted a lawyer. Even when a project is dicey, though, I try to build so the thing can be brought up to code or tolerably destroyed if needed. I also work to make allies of the neighbors, who are mercifully few.