Just wondering how many people have been suffering from CTD's at specific, predictable locations? If so, where?

My current nemesis is Riften (in the wilderness near the city), though it used to be Helgen but that's fine now. I've tried disabling mods, doing a complete reinstall etc, but nothing seems to have made any difference. (It's probably worth noting that CTD issues have been worse since 1.5 too!)

I know there have been a few posts suggesting file size can be a factor, but this is my second char (only about a month old) and 7MB so I wouldn't think that to be the culprit either. Maybe a navmesh bug? I do have a custom house near Ivarstead but nothing around Riften...