You've been on trips, your bike gets dirtier and grosser, both for road and mountain bikes. Things break and disappear. It's frustrating and then you wish you had more answers.
Part of planning a bike trip is getting the bike ready, keeping it in proper operation before leaving, and having a tech look it over as well at least a couple weeks ahead of your trip.
Things to look for:
With wheels still in dropouts/bike, grab the tire and wiggle it. If your hub is loose, it will manifest itself here. It is time for the cones to be tightened or new bearings. It could be a sign of something more as well. If it is fine, then you will feel no strange additional movement.
This one is mostly just nuts and bolts. The crankset is held in place one to several fastening and preload devices. To check for looseness simply grab the ends of the crankarms and try to wiggle them laterally, or side to side, to check for play. It will be obvious because it won't feel right. Something will feel loose if there is something wrong. The crankbolts may need to be tightened, the bottom bracket bearings may be bad, or there is something else going on down there. The reason this is important is that your crank arm could simply fall off during a ride. This happened to a friend of mine in the middle of the Whole Enchilada. Get it checked.
Chainring bolts are easy, just grab the appropriate size wrench and check to make sure they are snug. If they are not, then good thing you checked
Rest of the Bike
If you've found all the above secure, then go ahead and make sure things are snug, not over-torqued, on the rest of the bike: Stem bolts, both at the bars and the steerer tube. Pedals should be tight. Pivot bolts on full-suspension bikes should be snug as well.
If you failed in some of the above tests get to your bike shop, have them run through your bike. It may need something more than a tune.
On the trip
The bike is a super sensitive machine and has an output equal to what you input. So if you throw it in the back of your truck for transport there's good chance you'll damage something that wasn't supposed to be damaged, stanchions, derailleurs, etc. These are sometimes repairable. Mostly not though. Get a nice rack, transport your expensive machine in a respectable manner. So the rest of us don't make fun of you.
If your bike is running the way it should, then dusting the bike and lubing the chain is all you should have to worry about while on the road. That's why you do all the things above. Check out this field video I put together.