We would have been lost (and ran into another hiker who was lost even with GPS) with out our guide. Joli really knows the mountains and kept us going at a pace that ensured we would always arrive before dinner - which wasn't always easy!
One word of caution. This is not an "easy to moderate" hike in my opinion - I'm from Colorado. These sections are long with significant altitude gain over varied terrain and with some very exposed, steep areas and long steep downhills. BUT, the views are stunning, the people and guest houses where we stayed terrific. Think clean, comfortable hostel-like settings in most cases.
Some words of caution: You need to be in good physical condition, have the right equipment (hiking poles, good stiff-soled hiking boots, rain gear and layers) and be accountable for your own health and safety. You are hiking in developing countries with poor infrastructure for emergencies. Once you begin, there is no "easy way out" of many sections of this trail, a helicopter will not be arriving any time soon, if at all. But that's what makes it a "Balkan Natural Adventure!"