First of all let me say that if you have a trailer then you are pretty much all set.
Otherwise, this info will help to get things down to what you really need, and can carry.
Depending on your bike and how much it can accomodate, l want to come up with a gear list that is practical to load on.
Ernie Dube has a great rig on his Goldwing so here is a picture of his red cooler and what he did to the bike.
Notice that the lower the weight, the more stable the load is.
The Honda Goldwings have great locking bags and they keep things safe and dry.
Several other manufacturers make aftermarket hardbags as well as leather or man made synthetic bags.
On my first trip, I packed the bike and when I took off I realized that it was too top heavy.
I turned right around, and an hour later had pared my load down to essentials that you see in the picture on the right.
There are various ways to carry gear on your bike.
You can add saddle bags, tank bags and large duffels that can be bungeed to your passengers back rest if you have one. This picture is from New Hampshire with the gear on the bike, a 1980 Suzuki 750.
Now this is essential.
I found a set up at Wally World that was very reasonable and saved a bundle rather than buy a rain gear set at a motorcycle boutique style shop for 3 times as much.
Light gloves are great for rain if the cuffs extend over the bottom sleeve cuff.
You want to be sure that the cuffs seal tightly.
When you're riding with your arms extended up onto the handlebars, you would be getting the rain driven up your sleeves otherwise.
The same goes for the separation between the top and trousers part.
You don't want wind driven rain up onto the belly unless it's a very, very hot day, then who needs rain gear.