Where would the route go to/come from? What trains? What era? Please expand as I would love to see what you can think of because as you said Temple Meads is a beautiful station.
I would suggest something like the original Just Trains Bristol to Avonmouth. Essentially cover the Bristol area local services, down to Weston Super Mare, Severn Beach and Bristol Parkway plus the freight only routes from Parson Street to Portbury and Hallen Marsh to Stoke Gifford. Era anything before 2015 when a wide variety of different trains could be seen coming and going on various services - 143s and 150s on the local services, 158s on the Cardiff to Pompey trains, HSTs on the GWML and Voyagers on Cross Country. Of course being a BR Blue man, I would want this set back in the day when the Cross Country services were loco hauled, Class 45 or Class 47, the local services operated by a mixture of DMU types.
Route wise, I'd think Severn Beach - Weston Super Mare (2010) might be a good route with HSTs and Pacers/150s
