San Diego International Airport
A quick 5 miles/10 minutes up the road! The venue is also a hotel, so definitely check that out for accommodations while you're in town!
Probably not great! With a 4:30PM ceremony scheduled, definitely give yourselves a little extra time if you're not staying on site. You can expect some version of rush hour traffic so check the estimated times around 3-3:30PM and plan accordingly!
You can park in the hotel parking lot - wedding guests will have complimentary parking whether you are staying on site or not!
My first recommendation is to rent a car, if possible! San Diego is a big city and there's a lot to see, so if you're able to rent a car, you'll appreciate it! It's definitely a driving city. Uber/Lyft are also big here, so if you don't want to rent a car, you'll always be able to get a ride share if you're staying in the main areas of the city, but they can be pricey if you're going to a different part of town! There is also a trolley that runs between East County and Downtown San Diego. It's not quite comprehensive enough to depend on for an extended stay, but it'll get you between downtown and mission valley easily!
I know this may be shocking, but it is not always summer in San Diego! The average temperatures for March in San Diego are highs of 67 and lows of 54, and yes, it can rain! Definitely check the weather apps the week leading up to your travels for a better idea of what you can expect! It could be hot, or it could be a mild week! The 'winters' always keep us guessing!