I personally would not bring extra gas unless it was professionally installed as a secondary tank.
What I tend to carry:
First aid kit with trauma supplies (items for excessive bleeding, bandages, 4x4's tampax, tournequet)
Medications and personal items
Tool kit> build your own based on what you can physically do along the road side; socket set, wrenches, screw drivers, allen wrenches, wire strippers and quick electrical connectors, electrical tape, zip ties. Include a good knife.
Any small extra parts you think you need; plastic rivets, fuses, only practical items for quick repairs.
Small fire extinguisher.
Small air compressor and tire plug repair kit.
Bungie cords, rope.
Safety supplies (whatever you feel comfortable with); pepper spray, pistol and 2 extra mags.
Rags, windshield cleaner, spray detailer polish.
Maps or GPS unit.
List of phone numbers, emergency and contact numbers, doctors phone numbers.
Extra $ and credit cards
Rain gear
I usually carry gum and a bag of jerkey, 2 bttls of water.
This does not include clothing and hygenne supplies.
Remember....if you forget something you can usually find a place to buy something.
With the extra storage available on most Spyders....this is not a problem. I had a Honda ST1300 and carried all of this and more.
Lastly...............if you are single.......................AN EXTRA HELMET ! :yes::shocked:

hyea::doorag::lecturef_smilie::clap: