Your options are limited. While I believe Anthony Chabot is a decent park be advised that it will likely be a very heavy commute to Jack London Sq. My main concern would be security as Oakland tends to be a high crime area. Are they at least providing you car parking near the show?
You could look at BART for transportation and be much further away with a walk from the Lake Merritt station. I see CGs in Berkeley and Concord but don't know about them or BART access. Check the schedules and not the distance.
I've driven through Treasure Island MH and RV Park in South San Francisco and it's OK plus it's near BART. A BART transfer might be involved.
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Bob