Honestly recreating the Riviera Line with the scenery it shows would be absolutely phenomenal if executed right in TSW, and this time we could go further than TSC and even include the Avocet Line so you can complete the full run between Exmouth and Paignton. The route would come with the Class 166 from GWE as well as a GWR Class 150 and 158. These would be relatively easy to add as all three trains are already in game. We could even make the HST usable if you have GWE and also possibly include a GWR IET and Cross Country Voyager. The route length is perfect as you can do a lengthy run between Paignton and Exmouth as well as quick fast services between Paignton, Newton Abbott and Exeter St David's if you prefer a shorter run. Services included will be: GWR: Exmouth-Paignton (150/158/166) Paddington-Paignton (HST/IET) Paddington-Plymouth (HST/IET) Paddington-Newquay (HST/IET) Paddington-Penzance (HST/IET) Cardiff Central-Penzance (HST Castle Set/IET) XC: Manchester Piccadilly-Paignton Manchester Piccadilly-Newquay Manchester Piccadilly-Penzance Leeds-Plymouth/Penzance Edinburgh-Plymouth/Penzance Glasgow Central-Plymouth/Penzance Aberdeen-Penzance (I know it's being axed but it's iconic so I'd love this to still be included)
Both GWR and Cross Country continue to pose licensing obstacles. Best chance of this route appearing (and IMHO more interesting) would be BR Classic particularly when the diesel hydraulics were still in regular service. Sadly despite numerous requests over the 7 years (to date) TSW life cycle, DTG have failed to rise to the challenge and produce this route in any era - there many who feel it would have been an excellent first venture into GWR steam, until they also abandoned that in favour of 12 mile electric bus stop routes.