It isn't really harder, it's a little different. There are three things to consider:
Do you have a floating line for your present rod? If you do then you could begin fishing rivers with what you have already and then later on, if you feel it is right for you then you can consider other rods. You need not spend a fortune.
The Dry Fly 'Expert' blog may be of interest to you and could help you in your move to river fishing, particularly if you take up the dry fly. A good place to start with the blog would be
this post. When you read it down to the bottom just click on the "newer post" option and it will take you through a series of posts covering the move from stillwaters to rivers and streams.
You do indeed live near a lot of river fishing. It would be a shame to waste the opportunities...

richard