Since you have family, I would recommend staying in the rental in Mission Hills because you will be centrally located to everything: Coronado, and La Jolla. If you have a view of the bay from Mission Hills, then you can plan sunset dinners.
You cannot rely on public transportation, it is awful! You must have a rental car to get to these locations within 20 minutes time.
Downtown has gotten pricey, but there are tons of hotels and things to do if you stay there, and you can get to the Del in 15 minutes, to La Jolla in 20.
Mission Hills is definitely the ticket. You can slum it in Kensington (coffee shops, the Ken theater for indie films) the neighborhood is craftsman upscale, and you can access downtown or Old Town or La Jolla or Del Mar, etc very easily. It is a perfect choice.
Just chiming in to say San Diego, also. We went to CA for the first time last summer and my two boys (ages 20 and 17 then), just loved California…we ALL did. I’d go back in a heartbeat. We were not in San Diego, though, but that’s where I want to go next. I believe LA is just a 2 hour drive, so if you are going for a week, might be fun to visit there.
There are tons of day drives from San Diego…tons. Out to the desert, into the mountains, along the coast, up to L.A.
If the young people plan to stay with you most of the time, stay at the Hotel Del. you won’t regret it.
If they are going to want to go their separate ways, the Downtown hotels would be a better choice. Everyone can walk in different directions.
Even from Mission Hills, you will need to all hop in a car to venture further afield.
Sadly the Hotel Del is not in our price range 
I’ve never been to San Diego, but I would love to go. If you end up there, make sure you take a day trip to Catalina Island. Heard it’s lovely. I, personally, would not head there if the weather has a chance of being iffy. You could look into some other choices, maybe Las Vegas or New Orleans…there are tons of parts of FL that would be gorgeous in December…Miami you mentioned but there’s the Tampa area, Jacksonville and St. Augustine (although chillier because it’s so north) , Ft. Lauderdale area, the Space Coast area, Daytona Beach area, etc.,etc.,etc. I’d probably wait to go to San Diego in the summertime. What about Puerto Rico? Lots to do that doesn’t involve sitting on a beach all day…
We’ve been to St. Augustine twice over Christmas. It’s fabulous and I’d highly recommend it to anyone, but we’d like to go somewhere different. Likewise, Daughter and Husband have been to Puerto Rico. I did think about the Gulf Coast, if anyone wants to weigh in on that.
Oh, and husband and I have been to Key West, but not Miami.
Having traveled with our 3 now-adult children, the hotels have always been pricey. As a local and native San Diegan, I have to vote for Mission Hills. Staying a full week at the Del and crossing the bridge to other locales is not only outrageously expensive, but also not a central location like Mission Hills (just above Old Town). You can always get fresh tortillas at the Old Town Mexican cafe or Coyote grill.
If you stay in Mission Hills and drive southeast, you will hit the community of Hillcrest which is a very distinct neighborhood of the elderly and openly gay residents but it works well. It is a funky mixture of hospitals, community, shops, restaurants, coffee places. Very walkable and has a number of businesses that cater to visitors. My kids love the Thai restaurant there and there’s a chocolate shop on 5th and University.
There are a lot of nice hotel in San Diego, the hotel Coronado was a response to dwhite.
Nice to hear a shout out for Hillcrest! S lives there and I love wandering the 'hood. I stayed in Mission Hills for his graduation, and loved the easy access to many places, Mission Bay in particular. A great biking area and walking area.
You mentioned Venice…consider going to Venice, Florida on Florida’s southwest gulfcoast.just below Sarasota. Easy ride up to Tampa Bay area where there are plenty of things to do too.
We stayed at the Horton Grand Hotel, in the gaslamp district when we were in San Diego. We made reservations through hotels.com, I believe. It was convenient to walk pretty much everywhere (we didn’t have a car). We walked to a lot of nearby restaurants, could walk to and along the boardwalk that fronts the ocean. H found a small museum that he enjoyed exploring one day when I was at a conference. The hotel has a charm of its own as well.
When we went with our teen/young adult kids, we stayed further away at a suite type Springhill Suites or similar and had a car so we could go to the San Diego Zoo and Wildlife Park. We stayed a week there just before S started college. It was a different experience to have to get into the car to get anywhere vs. being in the gaslamp district and being able to walk wherever we were interested in going (or catching the free trolleys).
Thank you for the suggestions and sorry to have hijacked this thread!
Definitely not hijacking - just adding a dimension! I hope you have a great trip, dwhite!
Why go to a hot place when summertime is hot at home?
I live in the Bay Area, and I have gone to San Diego to be WARMER in the winter.
Trolleys are not free, they cite people who don’t pay at the stations.
@“great lakes mom”, my children absolutely love walking Hillcrest!
Day visit to Catalina would be difficult because you have to drive up to Dana point, San Pedro, or Long Beach, take a shuttle, walk around Catalina, take a shuttle back and then drive back down. If traffic is bad in OC, they will be stuck for hours.
Day visits to Disneyland are doable but I would recommend an overnight stay given my current age and fatigue.
If you can swing it, you must check out the Getty Museum in LA.
Mission Hills at that time of year will have northeast views to the decorated Sea World tower.
I wouldn’t recommend going to Legoland unless your kids or DH really like Legos. It’s geared for kids under 10. It is very expensive and food quality is not good.
So I’ve self promoted enough.
New Mexico, at that time of year, is beautifully decorated. It may be cold and wintry, but will feel like Christmas.
Miami, very busy and “Cosmo”, but lots of activities!
@mamaduck so sorry…I guess I read @dwhite comment and didn’t notice it wasn’t the OP…you.
Mamaduck, since you are not the one looking at La Jolla or Coronado, look at the hotels downtown. There is a lot you can walk to…and it’s convenient to restaurants and the like.
Aunt Bea listed out a lot of the things to do in and around San Diego. If the weather is OK…take a drive into the mountains to a little town Jullian. It is like a New England town planted in CA. But winter driving there could be nasty.
After reading this thread I’m really tempted to go to San Diego again for the Christmas holidays. DD is a college student so she will get a few weeks off. I have family in San Marcos but would be willing to stay in one of those hotels nicely decorated for the holidays for part of the trip. Maybe if a bunch of us go we could get a group CC discount on flights and hotels. Wouldn’t that be nice. Seriously there is so much to see in San Diego. I love getting away from cold winters.
I love San Diego as well. Have only been there in May and the fall, for conferences and once to drop S off for college in LA. Our family so far has always celebrated Christmas at home in HI, so I will be unable to join this fun excursion. Cold winters are not among my favorite things, nor are HOT places, especially when temps climb above 90 and 100! YIKES!
HImom, I have never been to Hawaii but I hope in this life time I get to go. Coming from Northeast I would probably have to take a break in San Diego for a few days though otherwise that would be a very long journey. Northeast winters are too cold for me.