The Hall Walk is great.
I’d also look at doing the coastal path the other way (south) towards Polkerris, then Par and beyond. There’s some decent sea views across St. Austell bay, some lovely secluded beaches and Polkerris has ‘Sam’s on the Beach’ and a decent pub.
You can do Fowey town in half a day if you don’t hang about. Then you could do the Hall Walk in the afternoon. Day 2 could be the coastal path as above. Then day 3 you have options:
- The Eden Project is great if you’ve never been. A lot of it is outside so don’t go if it’s raining.
- You could get the ferry to Mevagissey if you like being on the water (although Meva is just like a small Fowey).
- There’s the Lost Gardens of Heligan (also good).
- Lostwithiel, Looe and Polperro could be done in a day by car.
Loads of choices!