Dimension of Dreams; seeking advice on landscape, denizens, and potential encounters

[Captain Zimri]

My party of 5 might be traveling to the Dimension of Dreams in an upcoming session, drifting way off the beaten Adventure Path. Because this isn't included or even a suggestion within the book, I need to do a considerable amount of planning. Here's what I have so far, in regards to creatures:
I found the Nightmare Creature/Lord templates in Bestiary 4, so I'll be putting those to good use on various creatures within the Bestiaries.
There are a handful of interesting creatures in the Occult Bestiary, like Dreamthief Hags, that could be present.

Are there any players or GMs who have been to the Dimension of Dreams?
What did you encounter there (or, in the case of the GM, what did your party encounter)?
What was the landscape like? Were there any places where they could find treasure? How should I describe the setting?

Any tips and advice on the Dimension will be incredibly helpful.

[The Sideromancer]

This seems like a location that would reflect the people in it (PCs and/or natives). It's dropped that the DoD may connect to Leng,

B2, Denizen of Leng wrote:

Many scholars have argued over where the otherworldly realm of Leng lies—some believe it can be found among the Outer Planes, while others are convinced it can only be reached via a dimension of dreams.

so having a skirmish taking places between the denizens and spiders could be entirely valid. Maybe have one (or both) sides try to recruit the PCs.

[Captain Zimri]

A description of the Ethereal Plane, which is home to the Dimension of Dreams, says:

Ethereal Plane, PathfinderWiki wrote:

This plane has very little of what most natives of Golarion would call geography. It is a place of ever-shifting mists with little hard matter to obstruct the traveler. (source)

That makes me think that there would not be any sort of "terrain" to encounter while traversing the Dimension of Dreams. And this begs the question "How do things survive?" I picture this now as a VAST plane of flat land, with nothing obstructing ones sight except distance. I guess one could easily assume that the swirling mists offer some protection, but that kind of cover isn't reliable.

I'm trying to wrap my head around what this place looks like.

[The Sideromancer]

For the ethereal, yeah it's pretty boring. you can't see too far because there's mist everywhere. As for the dimension of dreams, things are much more interesting:

PFwiki, Dimension of Dreams wrote:

The borders of the demiplane are marked by a foam of constantly changing dreamscapes, each the dream of an individual sleeping mortal. These can be viewed from the Ethereal Plane and even entered by those with the appropriate magic.

When one enters the dimension proper, it first appears as a prosaic dreamscape of the visitor's native culture. However, those who travel deeper into the realm discover that it molds itself to dreamers' wishes, slowly becoming whatever they would imagine.

Sounds to me like you're going to have to research your characters' cultures. You may also want to google common dream symbols or somesuch.