STP's OK, but nothing spectacular. Somewhat ordinary scenery. IMO the only fun way to do it is as a one-day. That's more interesting.
In Washington, RAMROD (Ride Around Mt. Rainier in One Day, 154 miles, 9500') is a spectacular ride. Downside is that it's limited to 800 riders so there's a lottery now. It used to be it was less popular and you only had to sign up. Oh well. It's too late to sign up for this year, but keep it in mind for next year. I've ridden it many times, really fun, well supported.
RAMROD