I've heard of a truly brilliant Victorian suspended ferry which I believe is in Cardiff or area.
The Middlesborough Transporter Bridge perhaps, though its situated in north-east England and not in Wales?
You're bringing back a lot of wonderful memories. Some bittersweet ones, as well. I was engaged to a young lady that stays about 7 miles east of the castle,
and I used to go to nearby Bridge of Allan every weekend to visit my teenage sweetheart, back in those carefree years so long ago!