taters work, roasting ears are good. plain ole white rice is good.
course ya need a pot with a lid for rice(slowly pour white rice into boiling water. ratio is two water, one rice. stir it when it all gets in for a moment, reduce to slow simmer, put on lid and wait 20 minutes[longer above 4000 feet] )
taters and roasting ears can be wrapped in tinfoil and tossed in a fire, but the tinfoil is not 100% necessary. if ya can score some of the little butter cup from a truckstop they go well with corn or taters. roasting ears does well with being soaked a while before tossing in the coals.
gotta have salt at least, salt and pepper is better.
pears, apples, oranges, last a long time. bananas are good but don't last long. same with grapes. cherrys seem to last a while longer as long as they arnt crushed.
theres been some talk recently on the forum about really old traveling foods like hardtack and pemmican. takes some preparation in a kitchen setting really, but lasts a long, long time. course pemmican uses animal fats and chunks of meat so that might not be your thing.
I guess I went at the question with the idea of durable foods that are nutritious.