re: Backpacking pack size

38 is awfully small for anything more than an overnight. Add in food, water, cooking supplies, cloths, a jacket or cold weather gear, tent if weathers bad and it'll be very tight with shite hanging off. I'd go 45 at the minimum for two or more days. Plus, 45 is still carryon size and it'll be more versatile bc you can still longer treks with 45.