You'll probably want a flat Crit circuit or alternatively a flat time trial. Most road races will have hills in of some sort.
Before doing that though, you probably need to join a local club that races. You'll get used to riding in a bunch (less important if you want to TT) and be able to judge your fitness against other riders who are racing at the moment. A local club will also be able to recommend races appropriate for you too.
You'll probably want a flat Crit circuit or alternatively a flat time trial. Most road races will have hills in of some sort.
Before doing that though, you probably need to join a local club that races. You'll get used to riding in a bunch (less important if you want to TT) and be able to judge your fitness against other riders who are racing at the moment. A local club will also be able to recommend races appropriate for you too.