You could have success at either site. The in-laws location is clearly the easiest to work with insofar as signal strength and number of available channels is concerned.
This is a link to the SlingBox FAQ page,
http://support.slingbox.com/get/KB-2000571
This is a link to some of the hardware that can connect to a SlingBox,
http://www.slingbox.com/go/spcd
http://support.slingbox.com/get/KB-2000463
A Channel Master tuner such as the CM-7001,
http://www.channelmasterstore.com/HD..._p/cm-7001.htm would do quite well connected to an Antennas Direct DB2E antenna.
So one solution would be
At the receiving site:
An Antennas Direct DB2E antenna
A Channel Master CM-7001 set top HD tuner
A SlingBox 500
Internet connections capable of 2 Mb/s or better.
At the viewing site:
A Sony NSZ-GS7 GTV
(If you are comfortable with IP routing and setting up a VPN link between the two sites, a SiliconDust HDHR tuner and a PC would be the main components, supported by the VPN routers.)