Is there a "knit as you go" feature in RStudio?

I'm working on a long project that involves lots of testing of data. I'd really like a log or workbook of my progress, that can just display relevant plots, tables, test statistics, etc. The code chunks to generate it make the whole doc very cumbersome and I'm wondering if it's possible to just see the output in a working fashion.

extra rationale: Some functions take time to run. By the time I have a knitted doc with the results of 50 function calls, this could take minutes to run at the start of each session, just to get me back up to speed.