Where are the extra $17K going?
I'm guessing taxes. That would imply an average tax burden of around 15.5%, which seems right for Oregon (with federal + state income tax).
I'm slightly a bit more of a hippie than you are, recommending $40,000 per year spending outside of housing costs -- I took your $60,000 to include housing costs, so net-net I'm guessing that implies $45,000 per year spending outside of housing costs. And your suggested $1,500,000 net worth includes the house, while my suggested target is $1,000,000 without counting the house.
The reason I state my figures on an ex-housing basis is that housing costs can vary wildly depending on city and region, and most of that cost is positional and not really tied to objective quality. But the rest of cost of living -- food, clothing, transportation -- varies far less by U.S. region. Someone with a $1,250,000 net worth could have a nice paid-off family house in a good school district, and a million left over in investments, if he lived in El Paso, Texas -- or even Vancouver, Washington -- but probably not in Portland proper. On the assumption that the OP will stay put in Portland, I think he is looking at a total net worth of $1,500,000 or a bit higher, as you suggest, so my ten year timeline morphs into your 13.5 year timeline.
I'm glad to see my thinking more or less vindicated by the wisdom of the crowds!
I also lean in favor of paying off the house before formally pulling the "FIRE" trigger, because I find that most people who rely on passive investments sleep better at night when their fixed required monthly cashflows are as small as possible, so that market downturns scare them less. Other folks take the view that, mathematically and based on investment history, you're probably better off staying leveraged and keeping more investments riding in the markets through thick and thin, because of the long term growth, but doing that successfully requires a certain mentality that many people don't care to cultivate. And if an early retiree does get spooked in the middle of a downturn and sells his equity investments low, there is a good chance of wrecking the FIRE plan and having to go back to work.
Still and all, I'm just trying to err on the side of optimism for this young fellow -- keep numbers nice and round and motivating!