Sadly, "Battlefleet Koronus"'s release was pushed back on Amazon past the go-date of my RT campaign, and I was rather looking forward to having solid rules for how to handle armies, ground forces, their gear, and otherwise. How do you deal with that sort of stuff for your players?

A scaled-down version of the invasion/armies rules are included in the Frozen Reaches adventure.

Up until now when my group has run into an army vs. army encounter we play it out using the Warhammer 40k game rules. In other circumstances I simply narrate the battle while the PCs skirmish a key target that decides the battle's outcome.

Glad, then, that I purchased Frozen Reaches... I guess I'll check it out.