The first year the CBBB was held, I missed out on making my reservations in time and stayed at a motel in Bullhead City. It was $50 a night or so and I had no problems in the parking lot with the boat. They were able to give me a room that overlooked so I could keep an eye on it.
There's a public ramp in Bullhead you could use, and unless you get really really bad mileage/hourage your gas should get you there and back easily (with some running around in between).
Now I start looking for the signup sheet as soon as the CBBB for that year is over. I'll never miss making the reservaton again! It's really nice staying at the AVI. Lots for kids (big n small) to do, your boat's right there etc, restaurants, movie theater, kids play area. The only way ta fly.
Someone else might be able to assist with other alternatives besides what I did.