Very preliminary cost analysis for trip, if I am missing something let me know:

2,400 miles one way, average 35mpg = 69 gallons @ $3.75/gallon = $260

7 nights of hotel rooms (camping may be an option) @ $40/person = $280

Wear & tear on motorcycles (tires, oil changes, etc.) – rough estimate = $500

Food @ $5/breakfast, $10/lunch, $20/dinner per day for 8 days = $280

Gear will vary depending on what you currently own.

Double these costs (approximately) for a return trip = $2,640 total trip cost

To rent a bike (approx $750) and airfare ($145) = $1,715 total trip cost

Airfare and shipping for bike back to California @ $775 = $2,095 total trip cost