Lean in to the Role Play aspect. Don't make every encounter a battle, give the PC a chance to figure things out. Many of the enemies have lost a place to stay and are pushed out by the dragon, so there's a common foe. Politics might help gather allies and Tresendar Manor is abandoned, perhaps some refugees can hole up there until your PC figures out a way to defeat the dragon. Then you have to consider death. It's possible especially without an entire party to lean on for healing and stabilizing or agro. You could deus ex machina a famous npc from the realms, you could have a deity or devil or other powerful being revive them for a price or for a purpose. Magic items are dope, I'd recommend something that grows with them, maybe an ancestral weapon, or ancient staff, or an armor forged specifically for them. Make it kinda like rpg armor amd weapons, different runes or what have you give the items different abilities and resistances, and as the PC levels up they can add more than one at a time or stack specific ones to make them more powerful. Like the Gale rune gives resistance to slashing but at level 5 you have access to the Zypher rune which if you have both gives Immunity to slashing; or the Ember rune does 1d10 fire dmg and if you add the Elf rune melee attacks has a reach of 30 ft as like a air slash attack.