InfrequentFlyer1991

Hi everyone and my apologies if this is in the wrong forum - I'm a long time lurker and a relatively new poster!

I'm at the early stages of planning a trip for March 2021. So far, I have flights to/from San Francisco from the UK booked (I know, it's daft booking flights just now, but the deal was too good to pass up so took a shot) and I'm looking for a bit of advice on internal flights within the US as I've never experienced these before. We are looking at having a couple of overnight trips away from SF (at the minute I'm thinking Vegas and San Diego, but I might change my mind on the locations depending on what we want to do) but I wanted to know how easy it was to fly within the US? Also, is Domestic First class worth it, or am I better sticking with Economy? We will likely be travelling Hand Luggage only on these trips, although we may decide to take golf clubs with us too depending on where we go (I like the idea of going to Phoenix if we can get a tee time at TPC Scottsdale on the Stadium Course)

I typically fly BA (so oneworld would be preferred if possible) but from a quick look online, AA don't fly direct to Vegas or San Diego (they do fly direct to PHX which is where we would need to connect if going to either of these cities.

Any experiences of internal US flights would be greatly appreciated, along with any other possible modes of transport. I'm not really wanting to drive those sorts of distances again as we did a road trip in 2017 which was actually quite tiring as I think we tried to cram too much into the time we had.