I've hiked quite a bit at various times in Europe, mostly short hikes in Germany and Austria. Several years ago, my oldest son, Jacob, and I took a week long hike through the Black Forest, of which we made a Web journal. The hike was so much fun that when I decided to return to Germany this summer (to participate in a 2-week seminar at the University of Düsseldorf), I decided to take a similar hike, this time beginning from where I would land, in Frankfurt, and walking through the Taunus Mountains to the Rhein river (at Koblenz). I mostly followed the European Long Distance Trail 1 (E1), but jumped over to another trail, the Lahn "Höhenweg" (high trail) the last two days.
The E1 is marked with a white cross on a black background ("Andreaskreuz"), and runs from Italy to Scandanavia. Much of our route through the Black Forest also coincided with the E1. Good maps are a necessity for such a hike. I used two, both at 1:50,000 scale, the Kompass Wander- und Radtourenkarte Östlicher Taunus (3840) and the Naturpark Nassau map from the Landesvermessungsamt Rheinland-Pfalz. More detailed maps are also available. Maps can be purchased in Germany, or ordered, as I did, for mail delivery (from, for example, Amazon Germany).
Hiking in Germany is quite different from a jaunt on U.S. trails such as the Appalachian or Pacific Crest Trails. I don't recall the last time I turned a corner on the Appalachian Trail (the Virginia segment is quite close for us) and came upon an inn in the woods serving cold beer in liter mugs. It's not the same wilderness experience you have on American long distance trails, but, as in the frequency of places to eat and drink, it has its compensations. Tents are not needed since there are a variety of places to stay. In addition to hotels and less expensive pensions, there are youth hostels (of the places I stayed in Bad Ems and Koblenz) as well as lodges ("Hütten") run by nature or hiking groups. Wilderness camping is not permitted in Germany. There are campgrounds, but they are generally not attractive places to stay for backpackers.The journal for the trip was taken on a hand-held computer and pictures taken with a digital camera. More tech information is available for those interested.