Great, a chance to think about the TT course, thank you Flybri.
I am assuming that you will be on foot or public transport, the places mentioned are all good, and Braddan Bridge is accessible during races by the road parallel to the course. I have always found the buses quite easy to get the hang of, just remember to leave plenty of time to get to the vantage point you want and watch out for the roads closing times on race days. I have used the buses to get to places such as Glen Helen from Douglas quite easily, another option I would suggest is, if it is a dry, clear day, go to the far end of the prom to Derby Castle and take the electic tram to Laxey, then the mountain railway up to the Bungalow, I have done this a few times on day trips, it take a bit of time but you can see the wheel and Laxey while you are there.
IOM tours used to run coaches to the Creg and other places from half way along the prom - no sure if they still do, any ideas guys !
Mainly, enjoy it, it is a unique place, and if it looks quick on the telly then the first bike past will blow your mind. Roll on May.