A good starting point

With respect - there are umteen posts about this very subject already on here. Do some research by reading the posts and then ask some questions.

I am delighted to help those who have made some effort..

Cheers

HI,
First thing,
If you land early in the day, then OK, to start out there and then. If it' a late arrival, the best is to get into Negombo, 20 minutes from the airport , stay overnight, and set off in the morning.
As you come out of the front door of the airport arrivals, turn left, within about 50 metres you'll see an old ( red and rust coloured ) bus waiting. If you don't see it, ask and you'll be told where to wait and it'll arrive shortly.
Thats a free shuttle bus which will take you from the airport to the main bus stand in the little town of Katunayake. About a 10 ninute ride.
From that bus stand yu can get a bus into Colombo.

From where he bus drops you in Colombo, walk to Colombo Fort station and get a train heading south. The train line hugs the coast all the way down to Galle and then along the south coast as far as Matara.

If you decide to stay in Negombo over night, you can get the Negombo bus from Katunayake bus stand into Negombo and a tuk tuk from the Negombo bus stand to Lewis Place where there are plenty of guest houses and budget hotels.
Then , in the morning, a tuk tuk to Negombo train station, the train from there to Colombo and so on down the coast.
-----------------------------------------------------------------------------------------------------------

Or, if your budget allows, a car and driver is much easier. You can pre-arrane for a friver to collect you from the airport and just sit back in air-con luxury as he delivers you where ever you decide to stop down the coast.
Thats easiest but there's no fun or sense of achievemnet in that.. Plus, travelling around on public transport, especially the trains, is a good way to start getting a feel for the culture and the people.
---------------------------------------------------------------------------------------------------

Hiring your own car ?.
Just not worth it. The first hurdle you'd encounter would be geting through the manic trafic into Colombo , finding your way through the congested streets and onto the coast road going south.
That could take you a day or two.
Road signs are poor, when you get inland , sometimes non existant.
Trafic is manic
The road trafic rules in Sri Lanka are basically,
You drive on the left.... Unless the left lane is full,,,, then you drive on the right.... unless both lanes are full, then you drive in the middle and weave in and out between all other trafic.
Giving way,,, there's no real rules about giving way except that if it's bigger than you, move to another part of the road. Anywhere will do .
Do try, to not run over the animals which like to sleep in the road. Especially the cows because they make big dents in a car and that could be very expensive.

One other little point, if you've negotiated your way through enough trafic , sleeping cows and dogs, tuk tuk,s going at right angles to all the other trafic and you finally find yourself on the open road, don't relax.
Keep one eye on the road and the other on the verge. Constantly update your memory chip as to where the safest bit of road verge to hide is located. In other words, drive along looking, constantly for escape routes because sooner or later, probably both, two or three buses will come round a corner, driver three abreast and completely filling the road and heading straight for you.
Thats when you, need to automatically know where that escape route is because they will make no attempt at all to stop , slow down or allow you any room.

If you buy a new bike, here in the UK, it squeaks..... In Sri Lanka everyone rides bikes that are at least 1000 years old, were made by Mr Raleigh, ( before he was a sailor ) and travel along the roughest of roads without making as much noise as you'd expect from a church mouse. They are another menace on the road .
No one with any sense or sobriety would want to ride a pedal cycle on Sri Lanka's roads.
So, before setting off , to get the groceries or to go fishing, or whatever, it's the law that every cyclist has to be drunk. So , all the prospective cyclists sit around and have a competition to see who can drink most Arrack. The winner , ie, the one who is staggerng so much that he can't walk, wins and is allowed to go out and play with the trafic.
It's a national sport.
Buses also like to collect these cyclists and they use them as bumper badges on the front of their buses.

OOps,
I got to be a little facetious there.

Rod.

Cheers Rod,

Thats was very helpful. Not to mention
an entertaining read.I think the train sound like a
good option. The photo's look great too. I cant wait to get there.