You can get a huge amount of stone and wood by following the following steps: -
1> Build a castle with 1 ton stone and 1 ton wood (or as less as possible)
2> When the castle is built, extend the castle design to use 100 tons of stone & 100 tons of wood
3> As soon as you exit the castle design screen, demolish the castle. You now have over 65000 tons of stone and wood!