I just got a dual bottle set of Surf city garage, sealer and nano wax for about 8 dollars at a closeout sale, mothers synwax for 2.. 
The surf city sealer is really good to make the paint shine - apparently it lodges itself into the paint pores to make it shiny, it smells feels and spreads like 3M hand glaze (which I prefer) - but the incredible shimmer and shine of the surf city products really made the finish pretty, The nano wax jobbie enhances this shine further.
For the bus I would suggest 3M hand glaze, apply and leave it for about 4 hours in the shade, then replenish with some more glaze and gradually buff it off with a clean woven cotton cloth, cheesecloth or microfiber. Finish off with some HD synthetic wax of any brand. Reglaze in the next 4 months again as the paint is new.