Any slingbox or equivalent has to have control of the source device ( cable box, sat receiver) and anyone at the source has to watch the same thing. Or if they change the channel then then you also get the change at the remote device. If she has TWO cable boxes then you can connect to the one ( say in the bedroom) that she normally doesn't use , but the local user can still override you. The thing is streaming devices require a SOURCE device to connect to and control, as they have no tuner built in.
You will need the streaming device and a standalone ATSC tuner or other device it can control.
Also a good high speed internet connection is required to send the stream out ( 2-3 MBps for DVD quality out) and also a good download connection where you receive to get a decent picture. Sling and others will downrez the feed automatically to the available bandwidth. So you need a decent internet connection and either cat 5/6 or high speed wireless router.
Although the new sling 500 has HDMI in and out and can do true HD , copy protection can block the ability to record or stream that feed , so in most cases you have to connect via component cables ( and L/R audio ) anyway.
To stream true HD you need about 10Mbps upload speed. The sling 500 has wireless built in , the sling 350 does not and also has no hdmi connection.
A good alternative is the Belkin @tv Premiere device ( can currently buy at belkins home site for $99.) which has component and composite in and also wireless access. It is not as smooth to install as the slingbox but provides a decent stream ( DVD quality 720x480 is its max) which is more than adequate for phones or tablets. Also the apps for tablets and PCs are free with Belkin and allow you to record the stream on the receiving device, which Slingbox does not. For Pcs sling now uses a web browser to view the stream, instead of a dedicated app, unlike belkin. Phone apps are a charge on either, but sling has more phones available. Sling can stream to most media streamers like roku, etc. while belkin can't.
If you have windows 7 home premium on your PC you could buy an ATSC tuner card or USB tuner for your home PC and record the bronco games on it. If your video card can output in component ( or composite) video you could feed that to the streaming device, but you could not control it remotely.
Another alternative would be to simply use a Win7 home premium laptop and take the USB tuner with you ( you will need a good portable antenna also to get the signal). Win 8 also can work but media center is an option in win 8.
This would be the cheapest alternative if you have the laptop as the tuners only cost about 50-70 $.