Definitely sloppy execution and much time save to be had with better use of fast traveling on top of just not messing up inventory/dialogue mashing. Sub 10min is possible.

Route differences-

• Go directly to sleep in stables on Day 1 instead of entering the hotel
• Skip doing any of the gambling as now have enough money to buy all the necessary items to finish
• Skip Sheila's subplot entirely as don't need to go upstairs in saloon and talk to her to get the dice or use her room to sleep
• Skip Graveyard visit and family subplot entirely
• Sleep in barn on Day 2 and in morning can fast travel straight outside without having to unblock the door (go straight to the bridge if have it discovered). Unfortunately doesn't seem possible to do this on Day 1
• When lighting the lantern, take out a second match after and put it into inventory to prepare for lighting the train's boiler
• Skipping Sheila's subplot means don't need to pick up gloves
• Viewing the abandoned train on the telescope unlocks it for fast travel without having to walk there first
• Can fast travel directly to outside the church on the hill after the Sheriff fight