The views from Hidden Peak of the Eagle Cap Wilderness are amazing and worth the trip. There are a couple ways to get to Hidden Peak but the easiest is to purchase a day ticket for the Wallowa Lake Tramway ($38 per person as of 2021 - https://www.wallowalaketramway.com) to the top of Mt. Howard, and hike south along an unofficial ridge trail. If you are planning to backpack for a few days let the staff know you won't be taking the tram back down as the tickets are only good for one day and you'll need to hand them your ticket at the top when you disembark.
Park at the Wallowa Lake Trailhead at the end of Wallowa Lake Hwy/Powerhouse Road in Joseph, OR and hike the 7/10ths mile down to the Tramway. Once at the top of Mt. Howard there are a mess of trails around the top. Follow the wide trail further up the mountain (ask the attendants where the spring is to fill up your water, this will be the only place to get water). If you follow the ridge you will find an unnoficial trail to follow. As long as you're on the ridge heading south you're heading in the right direction.
You will be above tree line the whole time. Once on the summit you will have plenty of options to put a mast in among a bunch of rocks for support. 2m work will be difficult unless you can raise a couple local hams in Enterprise, OR who were happy enough to help us out.
The photo below is the view looking southwest from the summit.
