Sims Butte can be accessed via the Obsidian trail #3528.  This is within a high-use area and requires a $6.00 permit through www.recreation.gov.  Hike in about 3/4 mile and turn right off the trail to hike across a log-strewn area to the base of the butte.  The butte itself is heavily littered with downed trees and underbrush.  It is a tough climb, but fortunately the summit lies only about 500 vertical feet higher.  We used an old naked tree to string up the inverted vee antenna.