Short Version - the Mount Defiance hike from the gorge (north) side is a project, with roughly ten miles RT hiking and 4900 feet of elevation gain. But there are other options, including a southwest approach that is six miles RT and 1100 feet or so of climbing. This writeup describes the southwest approach on trail 413, which begins on Dead Point Road at (45.63628, -121.74261). The drive from Hood River is about an hour on a combination of paved and dirt roads. ATT cell service is good, it is usually possible to activate using just 2M, and there are lots of places to set up HF gear. One caution: this is a *very* popular hiking destination!
Long Version - This was my ninth time on Mount Defiance and my fourth activation. After the sixth gorge side hike, and feeling a little bored, I started looking at approaches from the south side of the mountain: Kingsley Reservoir, Warren Lake, and the south terminus of trail 413, on Dead Point Road. After having hiked all of them, I think 413 is the best of the bunch, so this writeup focuses on the 413 approach.
Get yourself to Dee, Oregon (45.58879, -121.62711) and Punchbowl Road, which is off of Hwy 281. Follow Punchbowl to Dead Point Road. Roughly ten miles later (45.63657, -121.74258) you will see a place to park on the left and a sign for trails 413 and 411 on the right. Park here for trail 413. Note: there is room for five cars and the spots are usually filled by 1100AM. Dead Point Road is mostly Prius-friendly but has lots of twists, turns, and traffic. Be careful!
A hundred yards or so in, you will encounter the junction of 411 and 413, with 413 heading northeast. The trail is in good shape and for the 1.2 miles or so, trends downhill. At this point it starts climbing 1100 feet over the next 1.5 miles. As with most trails in this area, there is some treefall scrambling but it is generally easy. As you approach the summit, you will encounter one last fork in the trail; take the one on the right and you will be on the summit in a couple of minutes.
On top, you will find a commercial antenna site, other hikers, and plenty of places to set up HF or other antennas. ATT cell service is good, so spots are easy, and you can usually activate the summit with just a 2M HT and a decent antenna. On a good day, the views are awesome. On a bad day, with rain or wind, you will likely be wanting to get your four and go down.
The drive from Hood River to the 413 trailhead is fifty minutes. The drive from Portland is at least two hours, so you may want to pair this hike with Greenpoint Mountain, which you can also reach from this trailhead.