Pretty good price....put the savings towards a down payment on a dually to tow it.
It has a 'dry weight' of 12,000# which would max out your '05 2500 SRW
Really need to weigh your truck fully loaded (camp ready....passengers, any stuff in truck, hitch etc.) to get the trucks weight. Subtract that from your trucks GVWR.
That will give you 'available payload'........pin weight
Using 20% of trailers GVWR will put you in the ball park as to what pin weight would be.
Keep pin weight at or below your actual payload capacity.
That will probably be around 12,000# (GVWR of trailer)