When selecting the lower Flight Levels for cross country work, particularly in aircraft with restricted forward visibility, be aware there may be large solid objects at your cruise altitude. They may be inconveniently painted colors which camouflage them in low overcast.
Found this picture in the bottom of an old file cabinet today. Took it from my Pietenpol on the way to Brodhead and Oshkosh 2000. The Alabama water tower says “Tuskegee.” Even when I was younger, stupid and without plans of living to comb gray hair, I never intentionally overflew a populated area at low altitude. The picture above shows a pre-GPS navigational mistake on a 1,300 mile flight intended to be done entirely over rural areas.