Two waterfalls, three days, one increasingly damp rain jacket.
This is the trip that got me hooked on Sri Lanka's hill country in the first place — start close to Kandy and work your way up toward Nuwara Eliya.
Both of these are reachable by tuk-tuk or a shared van from central Kandy — no tour guide required.
Bring a dry bag for your phone; I did not, and paid for it at St. Clair's.
The route I actually followed — adjust the pace to however much rain you're willing to walk through.