I think your golf course idea is excellent. It is a fun way for students to learn about angles and reflections.
I did some searching on www.google.ca to try and find some resources. I found the following links that may be helpful to you.
This refers to an article from The Mathematics Teacher that shares a similar idea to yours.
This is a mini golf geometry lesson
Mirror, Mirror: Reflections and Congruencies
Mini golf activity
Laws of Reflection
I also searched Google Images (images.google.ca) for “mini golf holes” and found a variety of pictures of real mini golf holes. These may be of use to you or you can try different search words.
Probably the most important element the students will need to understand (though not necessarily the terminology) is that the angle of incidence equals the angle of reflection. This is how we are able to guess at where the ball is going to end up if it bounces off a wall, by estimating the angles. Hopefully the websites mentioned above will have some helpful ideas.
Hopefully the websites are relevant and useful to you.