I am leaving for a 2 night, 3 day camp tomorrow and wanted to know whether I should offer Qasar namaz or complete namaz. the base camp is around 52 km from my home, and we have to trek for around 2-3 hours to reach the camp site.
Firstly, based on the distance of that (as you mentioned 52km...),so, it seems that you should prayer in Qasar form. Secondly you should note that there are other conditions for Qasar prayer too, for instance:
Based on Islamic Jurisprudence, a Traveller (whose prayer must be shortened, not complete) is:
A person whose travel exceeds the Shar'i distance, that is, the covered distance (whether going or going and returning combined) must be at least eight Shar'i leagues (approximately 45 km.)
From the beginning of the trip, the traveller must be aware of covering or exceeding the mentioned distance; and must remain so until reaching the distance.
The traveller must not cross his hometown anywhere within the mentioned distance; neither should he remain somewhere ten days or more.
The traveller must not travel for Haram purposes.
The traveller must not be of nomads who mostly travel.
Travelling must not be his job.
The traveller must cross the Tarakhkhus Limit.
For further information and source, refer to: en.wikishia.net