There is currently no Polish restaurant or shelter on Śnieżka, but there is a Czech bar where you can get something to eat and drink. However, make sure that this bar is open on the website: http://www.postovnasnezka.cz/
Karpacz offers many ideal places for a date. You can go for a walk on one of the many mountain trails, visit Krucze Skały, or go to the atmospheric dam on Łomnica.
