I’ve hiked Grizzly Peak many times. It’s one of my favorite local hikes. The trailhead is a short drive from Ashland and is accessible most of the year. It’s a relatively easy hike. The first mile or so is a little steep but once you get to the loop section the elevation gains are mild and short. The trail gets regular use so it is maintained well. I usually follow the loop counter clockwise. This way you save the best views for the end of the hike. The west side of the loop was burnt out several years ago and is pretty exposed. If you’re hiking it in the afternoon on a clear day sun protection is a good idea.
The hike is approximately 5 miles with under 1000ft elevation gain. There’s a outhouse at the trail head. There’s not a lot of parking at the trailhead but you can also park along the road. The road to the trailhead is a mixture of pavement and dirt. It does have some abrupt potholes in places so keep an eye out.
This hike is popular and can get busy in spring and summer months. If you prefer to hike with minimal crowds I suggest a pre sunrise start or hiking it when mild rain is in the forecast. Backpacker magazine featured the hike in a recent article The Best Hikes in Oregon, From the Mountains to the Sea . This is only going to make it busier unfortunately.