Did it when I was in my teens. Went all over the country and had a great time. Had a crash in our van when we hit a milk float in Kidwelly, South Wales. That was exciting. Had some good friends who did it. Train travel was cheap and a couple of older guys in the 6th form organised some over nighters to various areas. My dad even got me into Plymouth Laira, a notoriously difficult shed to visit. These were working environments tho, large engines, fuels, men working. BR used to run excursions to eg Windsor, Hampton Court or Fort William. These were not expensive so a fantastic day out watching trains or just visiting somewhere.