Problems in Marten's Bluff

[MaxDiaster]

This is my first time in Marten's Bluff. I used the catapult and climbed into upper area. Saw the two upper rooms, nothing there. Went downstairs and found the wall crushing rooms and center room with hanging dummy and elevator.
Used elevator and went down and got the "find the flag" quest. Went north and got supplies from Soroth (I forgot his name). Going south I come to a door? that requires an answer to a riddle for me to open. Don't have a clue what the answer is.
Further south is an area guarded by T'RAn sentinels that say "leave this area at once."
Going back up the elevator, I can see two rooms (appearing as blue boxes on the map) in the south-east and southwest corner of the castle. They appear to be on both sides of the locked door with across from the wall-crushing rooms. I can not find the entrance to these two rooms. What gives.
My questions are:
1. How do I enter these 2 rooms in the upper section
2. What is the answer to the riddle door in the lower section.
3. HOw do I open the locked door across from the wall crushing rooms.
4. Do these things become evident latter on in the game and maybe I should mess with these things now.

[Xignal]

Most of your questions will be answered if you go through the Swamp to the Mine Tunnels and use the mine cart to reach Lower Marten's Bluff. Taking the stairs upwards from there should lead you to the other section of the fort.