I know you can add html to an RSS feed. My question is should you? I've broken down and written an rss feed for the wife's blog. It works fine, I used C# and Syndication. It seems to me I can just put the entire contents of the blog post into the rss feed, instead of just a description. I can't seem to find if this is something you should do, and is there any benefit to doing so? Any opinions would be appreciated.
The entire page, probably not... the entire content, yes, definetely! Pages have a lot of data that's not directly content. Take this one for example. In a feed, stackoverflow should include things like the title of your question, the full question, tags, author (you!) information... as well as many links: to this page, to the answer section, but also maybe to related questions... etc.
However, it's pointless to include the top bar for example, or anything in the right column.
Adding the full content will probably decrease the number of direct hits to your wife's blog, but it will also increase the engagement in feed readers. It will also help with SEO... and much more. The more you do for your readers (save them clicks!), the more they'll probably appreciate it.