Patty's place is in the best location if you want to be at Mission beach. It is 2 very small blocks to the ocean and 2 to the bay. You could go to the beach and just head back to the unit to use the bathroom when needed. The unit has everything you would need. The kitchen is fully stocked with cookware and has a coffee maker (which is a must have). The patio was nice and if you want to do some grilling, there is a nice gas grill to use. There is a great bodega next door that has basically all of the staples that you will need for food and drinks. Patty has outfitted the unit well and she has everything you will need for the beach in the unit, including chairs, towels, toys for the kids and even some books. For the building there are shared bikes, kayaks, and SUP's. If the building is full with multiple large groups those could run out but we didn't have an issues there.
You are only about .4 miles to Belmont Park with some good food options and more a party scene for the beach. You are about 1.3 miles up to Pacific Beach pier which has more of a nightlife. It was nice that right around the rental there isn't much of a party scene so it kept the beach and area a bit more quite which we enjoyed. I loved running up the boardwalk and around the bay.
I know it says you can have 5 people, but I think with 5 adults it would be really tight, especially if everybody has lots of luggage. Having the two bathrooms was super clutch though.