Great question and I apologize for not posting an answer sooner.
At this time Trulia does not provide you with the ability to point your Trulia Blog to your other blogs, however that is a feature that we are planning to add in the future. If there are any other features you'd like to see on Trulia Blogs, please don't hesitate to let us know.
I think you are going to have to do a lot of copy/paste. I am in the same situation with my blog on my website and my blog on Trulia...
Really would like to know if there is a better way...
Can't answer your question, regarding Trulia, though.