Haystack Butte (W7O/CE-221) is located in the Crooked River National Grassland, which is part of the Ochoco NF. There are some private grazing lands around the base and at the very top that you'll need to avoid, but access to a large activation zone is available via public lands. Note that some online mapping platforms such as CalTopo do not accurately show the public/private land pattern in this area.
3620 is a fairly easy summit to reach and activate when visiting the Camp Sherman-Upper Metolius River Area. Access involves a half-mile hike up from Forest Route 1270 with about 300ft elevation gain. The downside to this summit is the area was burned badly from past wildfires and the hike requires a bushwhack up an abandoned fire road.
The summit is somewhat flat with a wide activation zone, but very brushy. There are some live trees to hang a wire, but a support mast is recommended. I had good Verizon service and was able to self spot.