Nicolai Mountain is a drive-up summit west of Clatskanie in northwest Oregon. The gravel road is driveable the ENTIRE WAY in any passenger car (totally Priusable). So if your GPS is having you turn up a 4WD track you are going the wrong way. The views from the 3,028 foot summit can be awesome - the drive has views of the Columbia Estuary that's fantastic. Note that there can be of OHV activity on these roads and trails, especially on weekends.
Middle Sister is in the Three Sisters Wilderness of Central Oregon and is a committed alpine climb - it cannot be considered a hike as there is not a 'trail' to the top.
Broken Top is in the Three Sisters Wilderness of Central Oregon.
Goat Mountain is a reasonable easy summit to access that's not too far from Portland. For anything but high clearance vehicles, the last 1.5 miles to the summit will be on foot, but it's not too far. This site is popular with OHV as I saw seven in two hours on a chilly and damp November weekend.
Start from Molalla, Oregon at the four way stop downtown and go 15.8 miles east on Highway 211. Turn right on Hillockburn Road and go past a group of three gates where the paved road continues through the open gate in the middle.
Sheridan Peak is on the east side of the coast range, about 23 miles from Carlton, Oregon. Carlton itself is quite out of the way, being about 12 miles east of Newberg. But it's a nice short hike of about half a mile through some nice second growth woods, and the road is paved the whole way! (I.e.: if your GPS takes you to gravel, it's not the right way...)
Palouki (Παλούκι, stake or fencepost) is an easy summit within walking distance of Skopolestown on Skopoles Island. The T1 trail will get you there.
There's also a road towards Moni Sotiros that the trail crosses several times.
Velanidia (Βελανιδιά or oak tree) is a near drive-up near Volos, Greece.
Pente Pyrgoi (Five Towers) is a great hike near Katerini, Greece of about 11km round trip and 600m elevation gain.
Clarks Mountain is just south of Seaside Oregon. The trail is about 1.8 miles of one-way hiking starting at a clearly marked trailhead on the very south end of town on Sunset Blvd.
For anyone heading up to Mount Hood or headed from Portland into Central Oregon, Clear Lake Butte would be a nice stop on the way. It's a well graded and mostly paved forest road, suitable for biking or bringing along those that aren't big hikers. And no one would mind arriving at a classic fire lookout.