Visit 'Greater Poland' for its history instead of its (mainly rural, unvarying) landscape. It is from here that the Polonian tribe forged the nation of Poland by joining its lands with those of 'Little Poland' and Silesia when its first dynastic ruler Mieszko I accepted Christianity along with independent status for these regions. The Piast dynasty that followed ruled Poland for over 4 centuries, initially setting up shop in Gniezno where legend claims that the father of all Poles, Lech, first sighted a white eagle's nest. That spot became the first capital, and that eagle still symbolizes the country today.
Gniezno is one stop along the 200 plus km long Piast Dynasty tour, which also includes Lake Lednica (with a notable ethnographic park) and Biskupin (a village with origins back to the Stone age and archeological digs to prove it). Another blast from the past worth appreciating is Kalisz which reaches back to Roman times and earned historical mention as far back as the 1st century. More recently, this region is renowned for its second capital Poznan, a commercial center where appropriately enough the first public signs of discontent with communism broke out in the 1956 riots.
Wielkopolska also offers up the typical castles, in Kornik (a hybrid architectural wonder begun in the medieval times and updated by Karl Friedrich Schinkel in the 19th century), Rogalin (in the Baroque-mixed-with-Neoclassicism style), Goluchow (for a French touch), and in Antonin (as a modern hotel where you can dream away royally).
For those interested in rails, a few narrow gauge lines still operate between Stare Bojanowa and Wielichowa, and Gasawa to Znin. In Wolsztyn, you can even catch a glimpse of a steam engine or two.
For something a bit different, visit the beehive skansen in Swarzedz where more than 200 different hives can be enjoyed.