Help! information for Sri lanka trip

Yes. Polonnaruwa is well organized ancient kingdom & worth to visit 3 hrs time need to complete but all together, not spread-ed ie why I said well organized.
So have 2 nights near Dambulla & do day trips to Sigiriya rock, Dambulla cave temple & Polonnaruwa.
Then 2 night at Kandy for more culture & do day trips to Nuwara Eliya as well.
Then come to Hikkaduwa beach for relax & on the way you can visit Pinnawala as well.
In Oct you will get enough sun shine but probably some clouds late afternoon or evening.
BR+

PS :You need to share arrival & departure dates with time to tune your itinerary.

Try to go for railway tour from Colombo to Badulla. You can see nice scenic locations. Also Colonial era railway station Bridges, viaduct and trains.

Airport-Sigiriya-Dambulla-Kandy-N Eliya-Haputale-Galle-Colombo-airport

Minneriya National Park is a good place to go for a safari tour to see elephants.

If you are planning to visit Pinnawala, meantime you can visit Kandy ! Temple of tooth and many more historical places around.

Thank you all, was looking around and quite overwhelmed with down south beaches. which places what accommodation you would suggest there! Thanks again in advance!

In Oct south & southwest seas are rough enough to avoid except beaches like Hikkaduwa & Unawatuna. Those two has a reef so at least swimming is safe behind that reef.