Since you posted your query in the power training forum, I assume you have or plan to have a power meter. I encourage you to buy and read Training and Racing with a Power Meter by Hunter Allen and Andy Coggan. It has some training programs in it, but more importantly the book will help you understand how to target specific adaptations with your training program. Nobody can recommend a training program without knowing where you are starting from, how much time you have to train, what sorts of courses you have available where you live, and what your objectives are (e.g., crits, road races, TTs, etc.). I agree with AOG that you want to build up your endurance to 2-3 hours/day, but I disagree that the build is not serious training. You can have a plan, even for the first day on the bike, whether you are starting from scratch or coming back after a long layoff.