Make sure that your side view mirrors are on tight... Common stuff, make sure you do an oil change, your spark plugs are good and your radiator fluid is full and still the proper color. If you've ever disconnected your battery make sure that it is hooked up correctly.
As far as the luggage issue, get some throw-over bags... Just purchased a set of Cortech throw-over bags and they work great, they have a handle, so you can take them right off of your bike when you pull up to a stop or your rest stop for the night... you can purchase a sister bag that goes over the passenger seat as well, and you'll have a slight back rest along the way... but a traveler's buddy bag would be best for that. Anyways, other options for luggage space, the side mounted chopper bag and the one that goes over the headlight as well.
Bring water along with you, obvious choice... I almost got lost on a desert road one time and was kicking myself for not having any water for myself, luckily found a gas station and loaded up on water there. Definitely plan ahead your gas stops... you're light coming on around 100-115 miles, plan the stations around that and don't push it paste 130 miles if you can.
One more, bring an extra headlight bulb, my headlight burned out on me on a trip up to LA, think it was because it got too hot because of the type of bulbs they were. Luckily it was only the high beam that burned out and I was able to switch to lows, but the trip home that night would have been better with some high beams.
Check your air pressure in your tires, maybe a good 42, 42 mix would be best for those long roads vs the curvy roads combo that you may encounter.
Bring extra glasses and gloves for at least 2 occasions hot and cold, night and day driving.
That's it... The others will probably come up with some better idea's. Have fun on your trip!