As others have said, the first step is to decide where you want to go and get the maps out and see what things are along the way.
We we travel we drive a lot in a short period of time too, but I like to drive during the evening when the others are sleeping. It works well for us. But it does take a toll after a few days. When you only have a certain amount of vacation you have to make the most of it.
On of my favorite tools for finding good campgrounds is
RV Park Reviews. Once you find a campground that you want to stay, look it up on here and see what others have to say about it.
But to help with other incidentals I have some follow-up questions:
What year RV did your dad buy? Has he driven something of this length before? Will you set it up to tow another vehicle behind it for sightseeing? Have you guys done any camping or RVing in the past? (and yes, they are completely different animals) When are thinking about going?
Doug