Well having worked on slot cars in between watching the 12 Hours of Sebring coverage yesterday and again this morning, I decided to lower the track and tackle these two plans, first making a stencil and then painting on direction arrows (chevrons actually) every 3-4 ft (except on the start/finish straight):

After this I cleaned the surface of Caiman Pond and poured on the "Realistic Water" before putting back on the track cover and raising it back to the ceiling (the water takes at least 24 hours to set):
