Our HOA keeps a Genisis at the beach on our lake that DOES NOT get maintained/cleaned. I was tasked with grilling hotdogs for our annual kids fishing derby as usual.
I followed my typical gasser start up procedure of all burners WFO to burn of the grates and started a similar fire in ours. It took probably 10-15 minutes to burn all the gunk out of it LOL
But, it settled in and the dogs were good. The kids got a kick out of the fire. The moms, not so much.
Sounds like you have a few fun days planned, ENJOY!