If the previous Flitwick route takes a meandering path towards the coast, this one is about as direct as possible. Same startpoint at Holgate, but you'll tackle the west hills on Cornell/Thompson rather than through the zoo, then quickly turn off Skyline to take some boring but reliable suburban roads (Laidlaw, West Union) towards North Plains. After a control stop there, it's straight west again on some backroads that dump you onto Gales Creek Road before it meets up with Highway 6.
You'll take Highway 6 for basically its entirety. Because it's the most convenient coast route out of Portland, it's well-traveled by bike campers and tourers, and it has a decent (not amazing) shoulder. Traffic is moderate (not amazing), including some commercial trucks and vacationing RVs. It does get drastically worse on three warm-weather holidays -- Labor Day, 4th of July, Memorial Day -- so I wouldn't recommend taking it by bike on any of those weekends. Otherwise, should be fine.
This one ends in Tillamook rather than Netarts, and I forget why I decided that. The highest pass on Highway 6 comes just nine miles or so after you join it, then you can cruise at a good pace for the rest of the way into Tillamook. If you can time it right so traffic is low, the road is absolutely gorgeous, and definitely worth traveling at least once.
Both permanents are reversible, but I haven't yet written up cue sheets for anyone who wants to use them going in the opposite direction. There is a bus service from Portland to Tillamook -- leaves Tillamook at 8:10 a.m. and 12:25 pm, or leaves Portland (from the train station) at 10:35 a.m. or 3:15 p.m.