100,000 miles is definately not too many miles for a Honda (I've driven my 150,000+miles, 1996 del Sol from Maine to Colorado, back, and then out again).You'll need to make sure the timing belt has been changed recently, also the power steering and alternator belts. Change you tranny fluid and coolant before you go, and change you oil before you go and when you get there. Change the spark plugs (if they haven't been changed recently). Also make sure the power steering and brake fluid are topped off.Make sure your tires aren't worn or low, your headlights are working well, along with you signal lights. Be sure your exhaust is solid and double check you tie rod ends and axles to make sure they don't have leaks or torn boots.If you can borrow an OBDII scanner from someone or if you have one yourself, bring it with you, just incase that pesky engine light shows itself.Other than that there's only one other thing you MUST make sure is in good working order: Your radio!Have fun on your trip.