Ok, I must not be as bright as the previous poster. I have been through every area that I can find west of Fort Remote. I have chased off Rentar and have gone back to the Castle and been given the mission to hunt down Rentar, but I still cannot get anywhere.
At this point the only remaining quests are:
Hunt down Rentar
Darkside Loyalists
Metal for Dawdy (bug)
Go to the Castle (been there done that, still there)
More Chitrachs (bug)
Abyss Report
Message: Spire Fort
Liberate the Spire
Message: Bargha
Essentially all of the remaining missions require you to be able to get into Spire Fort and the Abyss, but I simply cannot do it. I am missing something, but not sure what.
Thanks