Jane,
my advice for trailer purchase would be : buy now, get some time to check the usual areas for repair/maintenance before you leave. It's no fun trying to repair a leaking window seam, dry out soaked upholstery, and still stick to your travel schedule
.
Tires, hitch & trailer
lights, frig & stove, door locks,
propane,
battery, etc, etc. All fairly easy fixes if you have some time, patience and ingenuity. Not such easy fixes on the road.
As a tenter you will be well equipped to transition to trailering.
Going south for you "left coast" folks looks a bit different from the route us easterners take, but the goal is the same...Warmth & sunshine
We passed up Florida this Jan-Aprilto take a swing out thru Texas, New Mexico & Arizona ( got lots of good advice from this forum!)
We didn't find the temperatures encouraging us to go "up" to the Four Corners...we even had snow eight miles north of the Mexican border in Arizona in Feb
Might be worth checking the websites for temperature ranges in the months you are looking at. Take fleece and a cube heater too
Sounds like a great beginning to new adventures
Happy Camping...Alistair