| Mr.Fishy |
OK first start small.
one Town, you need a house to live in, a bar/tavern to hangout in and a few shops, smith, a tailor things the PC is likey to look for.
Next a small cast of NPC's Town folk and poeple in the town, bar keep, his daughter the saucy wench, the black smith and his errant son [side kick] a matronly seamtress that needs things deliverto the next village.
Then expand the town and world as needed.
A river or pond, a forest, some hills or a standing stone with strange carvings.
Keep it simple and grow the parts that get visited the most.
Since the character is a solo you may want to allow a side kick a NPC friend to help the character out.
Solos are fun but can be difficult. One guy goes down and it's a TPK.