You can grab the Hub and Spokes doc for free and totally run with just that for a goodly number of sessions. I mean the first time Adam Koebel ran BW on Roll20 Presents I think they went like 14ish sessions before breaking out any of the scripted stuff (Duel of Wits). They did use Circles and Resources, but that stuff is pretty easy to grok. (Though is not in the Hub and Spokes doc.)