There are three Wildcat Mountains in Oregon, so be sure you want the North Coast version south of Highway 26. The road to the trailhead is short and easy in any passenger vehicle, there's a good spot to park, and summit is in the Tillamook Forest, although the shortest access crosses private timberland. The hike is about 1.5 miles one way, and 400 vertical feet gain. This description I consider the 'no bushwack' version.
A friend of mine wanted to try a new, never before activated summit to start off his SOTA career and bring me along as his guide. Doing some preliminary research, this looked very much like a summit that would be very difficult to impossible to reach. From Google Maps, it wasn't too far from the road to the summit, but checking Google Earth, I could see that it was really going to be a steep climb for the initial part of it and through what looks like dense forest. I wasn't expecting that we would be successful. Luckily, I was wrong.
This is a drive-up summit near Tillamook in the Coast Range. Don't confuse this Peak 2260 with the other that shares it's name but is W7O/NC-101. (They are only 8 miles apart.)
Take Mills Bridge Road south from Highway 6 about 3.2 miles. You'll stay on the main track as you ascend this steep rocky road. You should be able to drive in a passenger car as long as it can handle a steep, rough grade.
I like big buttes, and I can not lie... 
I don't have much to add that K7NIT didn't already cover in her excellent report.
WW7D and I were in the area for the WA State QSO party (Salmon Run). This was the 2nd summit we did on this extremely wet Sunday in late Sept.
The road up to West Twin Butte is really fun... if you are on a motorcycle! The last 1/2 mile of this road is heavily rutted out, and would be a challenge for a high-clearence 4x4. Most people will probably opt to park lower down and walk up the road.
Today's attempted activation of Wilderness Peak W7W/KG-132 was my second attempt at my first SOTA activation. My cousin and I have been hiking all summer on various trails between Lake Washington and Snoqualmie Pass. In the last few weeks I've decided that I'd give SOTA a try. We made it up to the top of Wilderness Peak today where I was stymied by steady rain and radio problems. I called it a bust and will try again in a few weeks.
Browns Mountain, west of Sunriver, despite being pretty close to a paved road, was a tough bushwack for Roland-K7FOP and I, as we pursued several "shortcuts." So we recommend walking about 2.4 miles on forest roads, and a final steep ascent of about 1/10 mile. Total is about 900 feet of gain. If there's a better way to get to the AZ, please write up an updated trip report.
Bishop Mountain is an extinct volcanic vent on the rim of the Island Park Caldera. At the summit there is a fire lookout that is one of the few remaining towers in the Targhee National Forest. The 72-ft tower was constructed in 1937. Now on standby status, the tower saw extensive service during the Yellowstone Fires of 1988. The summit also has a couple of picnic tables, a cabin that is available for rent through the Forest Service and a fire pit.
Ochocco Mountains High Point could be considered a drive-up summit...for some vehicles. Although most of the way is paved, your low clearance passenger vehicle will have problems with the road in places where you can't turn around. A quarter mile of walking to the summit is recommended - it's a neat spot.
About 30 miles east of Prineville on Highway 26, turn north on Forest Road 27. This may be described as Grant Springs Road, or Summit Road, depending on your resource. This is near milepost 49.
Chase Mountain is in the Blue Mountains of southeastern Washington near the town of Dayton. There is no trail to the summit, but you can drive right into the activation zone. Park at the bottom of forest service road 6437 for a 2.2 mile walk or drive up to the top and walk out and back in as I did. There are a few places at the top to pull your vehicle off the road.