Call Lakewood and ask them about parking. I doubt you would find anything on that side of the freeway. Same with the Aquarium if you are indeed going to the one downtown. There may be a parking lot you can fit in close by.
Kemah Boardwalk is cool if you have kids. Otherwise go to the one downtown.
Rudy and Paco's is not a meal, it's an experience. Well worth the $$. Dress accordingly and enjoy.
It has been said that there are two types of people in San Leon, those hiding from the law and those that will soon be hiding from the law.