Hmm, I suppose you could try the Tapatalk app and see if your forum can be accessed using it. There is also the ForumRunner app (the app that this forum's app is based on). There's a lot of overlap between them, but some unique forums on each.
Or a third party browser. Atomic is cheap, simple, and works well in my experience. iCab Mobile offers a lot more features, but is a bit busy if you don't need them.
Other than that, I'm out of ideas. Sorry.