Just back from a 3-week cycle tour of Sri Lanka. It's the most amazing place I've cycled so far - perfect road surfaces (on the main roads which don't get that much traffic), stunning scenery, friendly people, ridiculously cheap (£300 for 3 weeks including accommodation, food, tickets for national parks, buying clothing, etc).
The only slight hiccough was the heat/humidity which caught my friend out on the first couple of days. He suffered badly with hyperthermia and just couldn't turn the pedals - had to use public transport. He was fine eventually & managed to get up the steep hills by week 3.
Can't recommend it highly enough. A taste of what to expect:
https://youtu.be/voAfvdM6T-o