The Barlow Road was the final overland segment of the historic Oregon Trail used by pioneers in the 1800s to travel from Missouri to Oregon. The road was notoriously dangerous, and wagons sometimes broke their wheels or axles on the rough terrain. Travelers risked snake bites, bad water, broken bones, and diseases including typhoid fever, dysentery, and measles.
Lake Oswego has its own notoriously difficult road: the Barton Road. It is rutted, narrow, and unpaved; the large, deep potholes can actually break a standard car.
Your first challenge is navigating Barton Road. I highly recommend accessing the cache from Childs Road to the south, and turning north onto Barton. Your second challenge will be making the very tight turn into the small parking lot off Barton on the west side of Sunny Slope open space. You can also access the cache from the east (Eastside Road), but please be respectful of driveways there and do not block anyone. Other challenges include finding the correct trail, and avoiding poisonous plants (poison oak) in the sunny spots along the trail. (The cache itself is in a shady spot and I saw no poison oak nearby when I placed it.)
For your own safety and the safety of your car, DO NOT try to approach the cache from north end of Barton Road unless you are walking, mountain biking, or driving a high-clearance 4WD vehicle. (Seriously. I’m not exaggerating about the potholes.)
Good luck. Hope you don’t die of dysentery.