About ⅓ or a third of the way, you can stop at West Haven, OR. This is about 4 minutes southeast of Cedar Mill.
About ⅔ or two thirds of the way, you can stop at Portland Heights, OR. This is about 7 minutes east of Cedar Mill, or about 3 minutes southwest of Portland.
If you drive straight through without stopping at all, the total distance is 7 miles. The distances shown above don't include local roads to get into each town, so if you're planning a long road trip, make sure you factor in traffic and road conditions, rest stop breaks, and interesting detours along the way. If you're in a rush, you can do the trip with zero stops, and your total travel time would be around 10 minutes.