You can go here by train from Malmö, or from Copenhagen Airport. Flying to Stockholm (Skavsta) is another option, and driving down the E22. Kalmar does have an airport with connections to Stockholm Arlanda.
You can walk to all interesting locations. The city centre is relatively small, with two main squares. On one you find the cathedral (Domkyrkan) and the other is called Larmtorget. From the second you you can walk to the Baronen shopping centre. You an also rent canoes at the low cost hotel Svanen, and you can paddle your way around the centre, which is an island.
Kalmar is an interesting town in many ways. The town is old, and has some interesting architecture. The Castle dates back to the year 1160 A.D. It is also connected to the island of Öland by a bridge, which used to be Europe's longest (6 km). Kalmar is about 45 minutes away (by car) from the Glass Kingdom (Glasriket)where the famour works of Orrefors, Kosta Boda, Nybro, Pukeberg, Målerås are located. Kalmar has a football team, Kalmar FF, that won the Swedish cup in 2007. They play in the highest division, the Allsvenskan. You can watch them play at Fredriksskans, one of Sweden's prettiest football stadiums.