I've been using all of the host caches you mentioned and router.limwire.com:6346 as well. All of them have been effective in establishing a connection. Strangely enough, I've also discovered that connect.newtella.net is still functioning. I would have though that it been abandoned since the associated client Newtella is no longer actively being updated.
Have you considered that the problem might lie with your ISP, or more likely those damn firewalls that so many people feel are necessasry. I shut mine off whenever I use the Gnet; I'm just fearless or stupid I suppose.