I'll use crude Microsoft Paint maps to show number of ships and their 2D positions. That along with description updates should give you a solid visual of what's taking place. As far as Captain to Captain RP those opportunities will popup through communication links and occasionally boarding each other's vessels for personal meetings. As the campaign gets into motion you'll have a few repair stops to huddle up with other PC and NPC commanders.
I'm planning on having one Admiral position, three Commodore positions, and with approval, one accompanying Astartes Strike Cruiser w/Captain. And of course a dozen open Captain slots should we need them.