I don't think the router is specifically needed. If it's a cable modem, you should be able to just plug straight in, have the Slingbox lease an IP and go. IMO it's BETTER to have a router for protection. Also, I haven't tried it but if you have a VPN capable router you might be able to update the firmware over the VPN. Otherwise you'd have to have a PC or laptop local to the box. As for the DirecTV DVR, no, it won't interfere at all. I have a mini-CATV system at the office with 12 DirecTV receivers running off one dish. I have two slingboxes running on two of the receivers without a problem. You'll also be able to use pay per view and other features as though you were local to the box. That's why I also have a Slingbox at home running off it's own Time Warner cable box. The Video On Demand is AWESOME to have while on the road and satellite doesn't have that.