Help! I need brown bag lunch ideas - no more drive thrus

Hi,
For my work visiting hospice patients, I drive all over 4 counties on a regular basis. I need to start packing a lunch instead of hitting McD's or Taco Bell. I used to make myself a PB&J or pack leftover pizza or burritos, and I want to eat healthier.

I need lunch ideas that I can pack into a cooler/lunch bag that don't need to get reheated (no access to a microwave on the road). Just the two pieces of bread for a sandwich seem to add up to a lot, but I'm new at this.

Can you offer me some healthy suggestions?Maybe your favorites? I would appreciate it so much! I feel like I'm in a rut of unhealthy lunch habits. I do enjoy cooking, so I don't mind if some ideas involve a lot of prep.

Thank you thank you!