As long as channel 45 on your radio is not a repeater channel you can use it for simplex. At least that is what I assume you mean when you say "just for my family." You will have to check with your local emcom groups to see it they use GMRS, what channel(s) they use and what tones they my be using. As far as off-roading, use whatever channel or channels your group wants to use. It's always a good idea to make sure you aren't stepping on any conversations already in progress.