The new DVR will require the 5 lnb dish, which, unlike the past is fairly difficult to set up without the proper tools (meters etc) ALso, no current installed multiswitches are compatible with the new system. There was only one available last I loked but can't remember who made it for the new system. I don't know how you will mix and match the new with the old. It MAY be that you will keep your old systems installed and install the new one in addition. One more thing. You can't diplex OTA signals with the new system either so if you need OTA reception you will need at least one additional RG run to each receiver location.
All in all, you may want to run your own wires, but using a DTV installer MIGHT be a good option, especially if you can get someone good (read not free)