Here's an easy road walk in Eastern Oregon of about 2.1 miles round trip and 400 feet of gain. Interestingly, there's only one "Lake Butte" in Oregon - and there's no lake near it.
About 3.5 miles west of Prairie City on Highway 26, go north on Road 18 or Bear Creek Road. The road name may change to Keeney Forks Road and is paved most of the 15 miles you'll travel to find your way to 44.587°, -118.903° - the junction of NF-279 and Road 18 From here it's just over one mile to the summit. You may find some of this road driveable in your vehicle - we decided to park and walk the quiet forest road. There may be signs for the Nipple Butte Trail, but we didn't find much evidence of a trail that would lead to that summit over three miles farther west.
There are some trees at the summit for rigging antennas, but it's mostly exposed. We did by chance work someone on 2m FM as they were passing along Highway 26, but otherwise all contacts were on HF.