What to do next?

HI All. I’m just about to finish the ‘Build Me Up’ training plan and already starting to feel like I’m going to miss the structure of a regimented plan. However, I don’t necessarily want to hammer it with 4-5 training rides per week forever - it would be nice to do some racing and just get out there and ride. So, do folks have any recommendations of a good top-up plan or regime to keep the hard-won fitness levels up with maybe 3 training rides a week?