The Fleetline is very easy to repaint. An exterior repaint can be achieved by using the white body texture files which come with the model. Using Paint.NET or similar image editing program, these should be applied as a "multiply" layer over your paint base layer.
To change the interior of the bus you need to repaint the SF_in..... and LF_in..... files according to whether you are doing the short 30' Fleetline or long 33' Fleetline respectively.
To get it to work, starting from scratch you need to download the two Metrobus files from the Google drive on here: https://www.facebook.com/SWIBus and then apply the patch. It doesn't work on top of an original install of the bus by MAN1333.