If you like Scottish Stories, you ought to enjoy this one.
I doubt it is anything like the movie, though I've never seen it.
Curiously the character Rob Roy only shows up very briefly in the beginning, then doesn't make another appearence 'til the middle.
The real hero of the story is an Englishman who has no idea what is going on half the time, which makes the story at times a little confusing.
A WARNING: It will take you time to read the book! The Scottish Dialogue is not the sort you can just buzz through. Here is just a sample:
"I hae kend mony an honest man wad na hae ventured this length."
I haven't made any typos there... that is how it is written!
Thankfully, the narrator is Sassenach (an Englishman) so you can get through the main story easier. In the end, it is worth the effort!
This one starts out dreadfully slow, but after about 30 pages, it picks up a fair bit. It has a few things that seem odd, and reading in Scots is a bit of a challenge.
Note: the 1995 movie is not based on this book. I checked to see about the movie when I was nearly done, and found this out. Which bummed me out a bit, as I hoped to see the book play out in a movie form. Perhaps an older movie version matches, I don't know.