There is a tortoise pen to the northwest and a terrorbird pen to the west. The tortoises drop decently high priced tortoise shells for Summoning, but can hit pretty high and the mounted ones can hit higher. But you can visit swamp for food - don't forget to pull off the frogs' legs first.
Note that the first time you enter there is a small dialogue with Femi.
The Gnome glider hub is located on the top level of the Grand Tree. Easiest access to this network is through the Al Kharid lodestone, but this network also connects to the fairy ring network and other useful locations.
There is a mining location under the tree, accessible only after you have completed The Grand Tree.
There are three convenient banks in the Stronghold. One is located on the 1st2nd floor[UK] of the Grand Tree, and another is to the south and to the west of the agility course, conveniently near the yew trees, magic trees, and flax.
Some players experienced a glitch following this graphical update in which the area would get stuck when loading.
There is a Willow tree near the Yew trees; which is odd, because this is nowhere near water, and Willow trees typically grow near water.
A gnome can be seen trapped on the cliff to the east of the stronghold, next to Baxtorian Falls.
On March 2012 a small pvp zone existed north of the grand tree. It is only 2 squares north to south but it is undetermined the length east to west The option to attack was given, the skull icon is in the corner, and it is listed as a multi combat zone. However players could not attack each other. It was fixed in an update a day later.