Let me see if I can answer some of these questions:
First, here's how you can access the RSS feeds. From within the forum level, click Quick Links on the navigation bar. You'll see items for RSS 1.0 and RSS 2.0 at the bottom. Click one of those (I use 2.0). You'll then get the RSS feed displayed and the URL in your web browser address bar. You can use that URL to subscribe to the RSS feed in your preferred RSS reader.
1. offline ability.
The RSS feed (I've only looked at the 2.0 one) does contain the full text of the post, so you should be able to see the entire post.
2. forum hierarchy.
I haven't seen this happen yet. I'll see if a couple of the readers I use allow me to view this thread as a thread.
UPDATE: It looks like only the original post is in the RSS feed. Bummer.
3. some ability to sync between the desktop and a Windows Mobile device would be nice.
Both
NewsGator and
Attensa support this. You can access NewsGator via its web client, FeedDemon, or NewsGator Inbox (for Outlook). There's also a beta for a Windows Mobile client (
http://www.newsgator.com/NGOLMobileBeta.aspx )
RSS is designed for syndication and not forum subscription. As a result, it's not really into forum features. Also, it's not designed to be an interactive forum or offline posting. Posting would be done through a blogging client, but that's not supported in forums.
I hope that helps some.