Before ditching the front rack/bags, I would seriously evaluate all of the gear you are planning to take and try to pare it down. Get rid of any items that are non-essential. Bring clothes (cycling and street) that are light weight and can be easily washed in a sink and dried overnight.

Years ago while still in college, I spent a summer backpacking on the Appalachian and Long Trails in Vermont. I started out with about 60 lbs of gear in my backpack, and the frame cracked during the first week of hiking. At the first town stop, I went through all of my gear and mailed home about half of it. Got rid of all sorts of things I didn't really need, including a SLR camera, fishing gear, books, sleeping bag and some clothes. It made a huge difference.

The past two summers, I have ridden week-long loaded tours of the GAP-C&O Canal trails. My total load both times was about 20-25 lbs max, mostly carried in rear panniers. We didn't camp out, so that helped a lot in saving weight. I carried 3 sets of cycling shorts/jerseys and light street clothes that could be easily washed by hand and dried. I could have dropped another 5 lbs by reducing changes in clothes, not bringing any books and less tools and gear. However, we found that 20-25 lbs was a reasonable load to carry and the trails are flat.