There aren't really many house rules for Beach Patrol.
Dramatic Knockout: This is more of a clarification really: As written this optional rule makes it harder to knock someone out when attacking with advantage as the rule is triggered 'If all your attack dice show “5” or “6” on their face the, opponent is immediately knocked out for 1d6 minutes.'. Changing this to 'If at least two of your attack dice show “5” or “6” on their face the, opponent is immediately knocked out for 1d6 minutes.' means it's more likely to trigger Dramatic Knockout when attacking with advantage.
Experience Points: Beach Patrol omits rules for XP, possibly deliberately for the sake of brevity or to make the game feel more episodic. I'm going to plug in the standard TinyD6 experience rules with a change for the vehicle rules. XP is accumulated at a rate of 1-3 XP per session and can be spent as follows. 6 EXP: Increase Stamina by 1. 8 XP: Acquire a new vehicle proficiency or mastery. 10 XP: Acquire a new trait, up to a max of 7.
That's it for now, I'll add more if and when they're needed.