I will be in LA for four days and would like to know if getting the Metro 7-day pass is enough. Or should I also buy a DASH pass, or just add some cash for non Metro transit.

I will be staying somewhere in the Arts District and my planned itinerary is as follows:

Day 1: DTLA Exposition Park
Day 2: Getty Museum Santa Monica Pier Venice Canal
Day 3: Griffith Observatory Hollywood

So far, the only uses for DASH that I found are taking the DASH A bus going to the nearest Metro Station, plus visiting the Griffith Observatory.

In addition, is there an app where it would only give you Metro bus/train options when planning your commute? I'm also thinking of going to the Randy's Donut that was feature in Iron Man 2, but it seems the Metro bus options are limited.