I'm originally from Aberystwyth, some great biking roads around there. Llangollen has great roads around it including Horseshoe Pass. Someone mentioned Brecon Beacons which I agree but just watch out for Kamikaze sheep, and if your lucky you may hear the army drills! Snowdonia and the north west of Wales has great roads to explore.
If it was just during the day I would say its parents lack of discipline but if their waking during night several times and as their 3 years old it might be Autism or other similar Learning Disability. Due to the wide range of spectrum of Autism and Aspergers it can only be looked into once children reach rhe age where there development os more able to be compared to other children. Sadly you do have to persist with doctor to look into it as it is still a specialist area.