I think, the Curonian split is the same from both sides, Lithuanian and Russian side. So, if you are interested in only Split - you should not bother about visit the Kaliningrad. But:
As I've already said here, my mother is from Kaliningrad, and I've been there near half of my life, especially during summer holidays. I love this town, and my opinion is what you should visit it near for week. And what's why:
The symbol of the town is the Königsberg_Cathedral:
In 1982:
Nowadays:
Cathedral
It is reconstructed now (and some work is still being made, but economic crisis brought some problems for this process), it's works as catolic and orthodox church, and has two museums inside - the Kant's museum and Cathedral history museum.
Also there is the Kant's Tomb:
The fishers's district - this a small place near the Cathedral where you can get funny photoes, try some sea food and so on:
Door to nothere
Romantic bench
Pirate with monkey
Modern sculpture
Money bird
the Amber museum. Very beatiful, amazing work inside.
- City near Kaliningrad - Svetlogorsk. Small beautyfull city with many great places to walk and huge amount for the buying something made in amber.
- If you are sea-interested person, or you are traveling with kids, you could be interested in visiting the Zoo
and Sea museum
- A lot of ships are available for visiting, such as
Vityaz:
Submarine B-413:
Cosmic ship:
- Marine base in Baltiisk:
- Reconstructered King's Gate (museum inside):
- Restaurants inside old forts all over the town (on photo - Wrangel's cafe):
- Fort Friedrich Wilhelm III - memorial of the Second World War - for the extreme trip. If you can, find locals to get inside the memorial. It is awesome!
- And a lot lot more. You can even made a trip to the Gdansk - the buses are regular, 6 hours - and you are on place.
Some reports with more photoes (in Russian):