Yes, I found the barrier. I enjoy mostly just exploring the map, not quests. But I'll get back to it.

Levelling: I went through a couple of mines/forts/etc between Sanctum and Giliad going cross country, got to level 11 and I'm a lousy player. Couldn't beat the ghost in the Erothin burial chamber. But the trail East from Sanctum has easy kills. The diseased deer! How to cure oneself? Hard to find cu...

Ditto!

I found the path--my mistake--I should withdraw the bug filing.
I notice it's impossible to reach the other kingdoms across the red lines on the map. I'm going to try the Southern one by swimming along the coast (!).

I found a Sanctum in the Death area valley with a lake--the map showed trails but I found none going in
so I jumped into the lake, approached the Sanctum--but I cannot find any trail going out. I'm stuck.
Is this a bug? i filed this also in the bug section.

Thank you, the wiki is indispensible to me because I have sort of tunnel vision and cannot guess what I'm supposed to do.
The most fun I had in Oblivion was climbing the cliffs around the edges of the map, just exploring. (The colors here seem
washed out.)

I have no imagination and need a walkthrough to depend on.. After the opening walkthrough I wandered north to Erothin, gate was locked (but I see fixed in an update), I swam around to the port and got in that way--but now what am I supposed to do? Is there a walkthrough? P. S. The colors look dull c...