FE_READ_STATUS is good. That means tvheadend is now querying the tuner(s) and the HDHomeRun is replying to that. All is well.
Now we "just" need to get tvheadend to start scanning. Which is quite daunting to figure out the first time you need to do that....
You need to have tvheadend find Muxes and services/channels before you can use XMLtv.
What I usually do is go to:
1) Configuration -> Tv adapters
2) Choose an adapter
3) Multiplexes -> Add mux(es) manually.
It is asking for four things there - you tv provider should have a page somewhere telling what those are. Who's your cable provider?
(If you are lucky you can go to Configuration -> tv adapters -> Add DVB service by location - I don't see any US locations there though).