Robert,
You've already gotten some great input.
Especially look at what Dale, WB6BYU, wrote...it will tell you what data you need to plug into your "life equations" in order to determine the correct / best approach!
(what that means is....you need to answer a lot of questions, in order to get more definitive answers)
But, 'til then, let me add a few minor points that should help.
Oh, and we're assuming the communications requirement here is not for pleasure, enjoyment of radio, etc...but, primarily when needed due to other forms of communications are not operational.....so, this means planning on NOT having local infrastructure to rely on, yes?a) Your comms in/around the Los Angeles area (Newport/Costa Mesa, Orange, as well as probably Corona) is easily do-able with simple set-ups....(although the terrain out/over to Corona could require something bigger, such as HF radios either at home or in the cars....or, of course, use of local infrastructure such as repeaters, links, etc.)...but your comms out to the Surprise, AZ (Phoenix) area, which is 300 - 320 miles away, is NOT going to be covered by simple handheld radios (unless you're using satellite phones. LOL)
b) Someone from So. Cal. who is better familiar with the specific terrain (and VHF simplex comms paths) between the Newport/Costa Mesa / Orange locations and out/over to Corona, would be best to evaluate whether a handheld VHF radio would be able to maintain good comms out/over to Corona, via simplex (not thru any repeaters, links, etc.)
My guess is that this path (out/over to Corona) will need HF radios at home / in the cars, in order to get a signal over those mountains! (which means no simple handheld radios)
c) The comms path, from the LA area, out to the Surprise, AZ (Phoenix) area, which is 300 - 320 miles away, is NOT going to be covered by simple handheld radios....and, is going to require HF radios at both ends, along with decent sized HORIZONTALLY polarized antennas for 80m, 60m and 40m bands, and trained operators at each location. (although 60m isn't that well represented by most hams these days, due to its "shared"/secondary access, necessitating its weird channelization....it can be useful at times)
[at 33* to 34* Lat, especially in the coming 5 - 6 years, it's unlikely that the crit freq will dip below 80m...so, a good plan would be for a 80m/40m fan-dipole, or a 80m/60m/40m fan-dipole (even if loaded/shortened 80m legs), at each location....along with a simple/entry-level HF radio, power-supply, etc...AND sufficient battery-back-up power to power the radios....this would give you good, reliable comms amongst all of your locations...but, it's NOT handheld, and not very portable]
d) Instead of permanent set-ups, with dipoles, etc. (as I described just above in "c"), you could equip each vehicle with same HF radios and decent (big) antennas, and use a wire extended off the top of these vehicle antennas to improve your comms range to better / more easily cover the ~ 300 range out to Arizona..
This approach is very do-able, but please understand that while comms of a 10 - 20 miles is easy-peasy (such as with simple handheld radios) and comms out 1000 - 2000 miles is also fairly easy from mobile / vehicle set-ups, it is ironically the "regional" coverage of 100 - 400 miles that is difficult from vehicles (hence why my initial recommend was for home stations and dipoles).
Robert, I won't ramble on anymore now....as we all kinda' need to know the answers to all of Dale's questions before we could get anymore specific.

But...
But, one last comment here...
I'm a BIG proponent of ham radio....and, I've used it on-shore and at-sea, in calm/benign conditions and in middle of hurricanes, etc....so, I love that you're looking at ham radio! BUT...
But, a rather simple solution to your comms dilemma is Iridium!
A few handheld Iridium sat phones, and/or an Iridium base/mobile phone in each vehicle, and you're all set!
Just saying....many folks start a process into ham radio thinking it's a solution to their comms issues, without actually understanding what ham radio is and what is required.

I hope this helps?
73,
John, KA4WJA
P.S. In case you didn't cover this in your prep for your ham test....please read this here....this is FCC Part 97.1 Which is the very first part of our rules and regs (which are not only US federal law, but also codified by most other countries in the world)...just so you know what you and your daughters are joining is much more than just a "hobby":
97.1 Basis and purpose.
The rules and regulations in this part are designed to provide an amateur radio service having a fundamental purpose as expressed in the following principles:
(a) Recognition and enhancement of the value of the amateur service to the public as a voluntary noncommercial communication service, particularly with respect to providing emergency communications.
(b) Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art.
(c) Encouragement and improvement of the amateur service through rules which provide for advancing skills in both the communication and technical phases of the art.
(d) Expansion of the existing reservoir within the amateur radio service of trained operators, technicians, and electronics experts.
(e) Continuation and extension of the amateur's unique ability to enhance international goodwill.