Thanks for the replies everyone...
My second receiver is a D12/100. So then I'd be fine with SWIM? The reason I have an interest in using only one cable with the DVR is that there's a bit of a difficult cable run ahead of me. The coax cables from the dish are very accessible inside the house at the entry point. It gets challenging to run cable from from there to the DVR. It can be done but it won't be fun.
While I installed my own dish and ran my cables years ago, I've never messed around with SWIM. If everyone thinks it would be more advantageous to do the cable run instead, that would be the route I go. Otherwise, are there any tricks or issues with doing the SWIM that might be useful to know?
EDIT 8:50PM EST: Ok, I see why the SWIM option might be a little overkill... there's a bit of a cost differential between the multiswitch option and the SWIM option. That and for the sWIM, it looks like multiple things are needed as opposed to just the one multiswitch. I'm going to go with the multiswitch.