Belf, I know your pain.... I have the same problem and a lot of other people as well. There is no easy solution for this problem... Not yet at least.
All I can advise you is: Get a GM to reset your char back to your inn and skip Deepholme
PS. I can't enter Stormpeaks and Tol Barad either, so I advice you to not go there...
Wow, triple post.
Belf, this wannabe solution works ( How ironic). The first time I tried it, it didn't, but now it does! Just remember, when you use the repair tool, you need to do this again, cause repairing resets the config file
Just a thought about what might cause problems in Deepholm.... If you have view distance as high... the columns that reform (ALL at the same time) can cause massive lag. This may be contributing to deepholm problems.