I just did my first extended motorcycle trip, our honeymoon!
We're about to head back after a week, total fun, rode all over the place. Here's what I did:
Here's the skinny, due to some unforeseen circumstances we had previously canceled (rather delayed) our trip. At the last minute, things worked out, and we could go. This was the day of the wedding, planning on (and did) leave two days later. No time to shop for motorcycle luggage online and the selection at the local dealer was super sparse, small, and expensive. I bought two large duffel bags with lots of little loops for tying at Wal-Mart, for about $20 a piece. I also got that sissy bar bag that I've been SUPER pleased with at Wally World, for about $40. I don't have a luggage rack, but that bag sits just fine and doesn't slouch at all. It has a pocket for the sissy bar to slide into, sinches on tight, and because I'm OCD about wanting my luggage to stay on in a hurricane, I added a couple bungies to it as well. It has two loops on the bottom, ran bungies from that to the place where the sissy bar mounts to the bike.
Duffel bags have two ratchet straps looped around the saddlebags, and around the saddlebag mounts, ratcheted tightly (carefully packed so in those spots its just clothes, not camera/laptop, etc.) Then, I used a small bungie to tie the ratched straps together underneath the saddlebag, to prevent them from sliding outward and off of the saddlebag.
Finally, bungies on the front and rear of each duffel (not shown, hadn't done that yet), are run through loops on each side of the duffel, and to the bike, to hold the bags up close to the bike.
600 miles later, absolutely fine, nothing even budged, and 7 days later I'm writing this on my laptop, in clean clothes, with my DSLR camera charging, extra lenses and tripod sitting on a table, well, you get the idea. We packed everything we wanted in more.
The sissy bar bag was our 'en route' bag. It had the camera case (For pulling off the side of the road for a snapshot), a small soft cooler with ice and water so we could hydrate in this 100+ weather, some sunscreen, a first aid kit, and a couple bicycle cable-locks I used when we were stopped to lock my luggage and helmets to the bike. (not fort knox, but hopefully it'll steel any wandering eyes away, probably an unnecessary precaution but, I had those cable locks sitting around so I threw them in there)
I had planned on that being a one time setup but, it has worked so well I think that's how we'll do it in the future. Whiting57 will have a heart attack looking at it, he loves to tell stories of bungies and cables stuck in rear wheels but I think I took necessary precautions. Plus this setup was a heckuvalot cheaper than one of his fancy trailers
(Oh, also, not to pick on my wife or anything but notice how the far bag is stuffed to the gills? That was hers. Notice how the close bag is sinched tight and not even full? That's mine, and it has some of her stuff in it. hehehe) - Oh but that brings up a point. I gave her a bag to pack and then packed mine. This setup made low speed maneuvering a challenge because of the weight offset, and if you lean to steer instead of counter-steering, it would probably make it handle poorly. When we got to the first hotel, we evened the weight in the bags. Made for more secure strapping, and made it right as if it weren't there!
Edit: Oh, and there is a strap running in the back loops of the duffel bags with a bungie holding both bags together, also helping keep everything tight, up against the bike, and without shifting (even when riding the Ozark 'mountain' twisties)