If you're drivin' Honda, you won't worry too much. As long as you have just changed oil, oil filter, air filter, tranny fluid and filter changed? Check for belt condition. If belts have crackle on inside then replace it. Most alternator fails after 120,000 miles or more so If you recently replaced alternator. Is your battery new or nearing it's 5 year lifespan as dated sticker on battery?
I would throw in some commonly used tools like racquet, 8mm, 10mm, 12mm, 14mm, and 17mm, pair of pliers, screwdrivers (both phillip and flat head), cheap voltmeter, $5 small LED tatical flashlight (found by the cashier area at Advanced Auto Parts, tis flashlight so damn blinding bright!!), crowbar and duffel bag (to fit all tools in) and throw it in trunk. That's what I would do for long trip.
I've been driving long trip many times and rarely had problems. So just relax and take energy vitamins, water or pop to keep you going for long drive. Sometime I alternatively watch movie on phone (copied from rental movies using DVD converter for phone) and driving to keep me out of boredom (I just prop it where speedometer is) and I admitted I'm just a little crazy but I had no issue on my own way (just like checking speedometer then road).
Catty