Just wanted to update everyone - DTV sent out one of their more experienced techs on Saturday, and while the existing cable carried the correct rating, he was uncomfortable with the fact that there was at least one barrel connector in there. He was willing to let me sign a waiver and give it a try, but he cautioned that this could be a failure point years down the road that could become a thorn in my side rather suddenly. I elected to just go ahead and let him install a new line from the satellite to the SWM. We were able to run it down the valley of the roof into the gutters and down the backside of the downspout, so it is reasonably hidden. He did go ahead and mount the dish in the same location as the old one up on the chimney. We really don't get that much snow in our area, and when we do it usually melts off fairly quickly. I am going to set up an OTA antenna with the old coax lines so that we have something to fall back on in the event of snow or rain fade.
All in all, once we got the dish location worked out, the rest of the install went fairly smoothly. Thanks to everyone on this forum for all of the informative responses. I sure know where to go for knowledgeable help with my satellite questions! Have a great New Year!