Hi Karin,
first I had a bike for two days, rented from Sam in Crown Point (the shop next to the junction to Pigeon Point). It was possible to explore the triangle between Crown Point, Scarborough and Plymouth. I had no helmet and I do not know, if he offers helmets. The only part I did not feel safe was the road out of town from Crown Point. I know much more dangerous situations from bicycling in Vienna.
The scenic routes require that you leave the coast, but it will be hard to climb up the hills.
Later I had a bike from
"Tobago Slow Leak Mountainbike Tours"
in Grafton. Here is my description to find them:
http://www.alewand.de/fotos/tobago/mountainbike.htm
(Their web address does not seem to work in the moment). They have better bikes and also offer guided tours.
I rode from Grafton to Castara, passing the Waterwheel Restaurant, Les Coteaux and Moriah. If you have managed to get up to the View Point at Mount Dillon, you have a fantastic view over the coast. By the way, I wonder why there is no sign.
From Castara I used the bike to get to the beaches in the north, but it is much longer and harder than you might expect after looking at the map.
I tried to explore the area around Moriah, but when I had succesfully managed to reach Runnemede from Castara, I was too exhausted to continue.
The sun will be your hardest enemy. And it is not the heat coming from above, it is the heat stored in the asphalt. Here is an example what you might expect:
http://www.alewand.de/fotos/tobago/fo12.htm
I had two punctures during 6 days, so do not forget the fixing kit.
But even if you stay only in Crown Point center, a bike is very useful to have a quick look at the sunset or to have a drink at Hotel Conrado.
Greetings,
Achim
http://www.alewand.de/fotos/tobago/index.html