I suppose I'm the best person to answer your questions (because I drive a truck).
First of all, if you are going to take the southern route, let me ask a few questions.
Is your car equipped with a good heater/ac?
You will need both of them.
If you are going to go down I-5, remember you will have to go over the grapevine to get into the LA basin to pickup I-10.
That is a very difficult pull, even under the best of circumstances.
The same if you go down 99.
Then you will face LA traffic.
If you dont have experience in that kind of traffic, pulling a trailer could be a problem.
You will have another severe pull on I-10 just before you go into Blythe.
Actually there are 2 steep hills there, both of which can and do cause 18 wheelers to overheat.
And then in Az, it will level out, but there will be long stretches of nothing till you get to Phoenix.
Traffic there can also be a bear if you arent used to it.
In eastern Az you will run into a few mountains, but nothing real serious.
New Mexico wont be a problem for you.
As for a moving company, there are several advantages.
First of all, most of them charge by weight, not volume.
They will weigh the truckbefore AND after they load you, and see what it weighs.
They willalso have insurance on your stuff, so if it does get damaged or destroyed somehow its covered.
You wont have to worry about loading or unloading, and they will deliver it right to where you want it.
Of course, it is more expensive then doing it yourself, but if you dont have the experience pulling a trailer, its probably better if you dont try it.
In my opinion, based on what you have written, you will be better off hiring a moving company.It will cost you a little more, but it will be worth it in the long run.
Now, some advice about traveling that far, especially thru the desert.
Prepare your car and yourself.
Get your car checked and make sure you have good brakes and a good heater/ac.
Get your car tuned up first.
There are long stretches of emptiness, where you will have little to no cell coverage, so if you break down you might be in trouble.
Get yourself a cheap CB radio, so you can use that to get help if you need it.
Make sure you have full gas tanks before you head out across the desert, because once you leave the LA basin, there isnt really anyplace to get gas till you get to Blythe.
Then once you leave Blythe, there are very few places to stop for gas till you get close to Phoenix.
Between Phoenix and Tuscon it isnt bad at all, but once you get thru Tuscon it gets empty, with a few hills that might give you a problem.
If you are driving alone, dont be afraid to stop at the truckstops and ask for advice, especially if you havent driven that route before.
The drivers will give you their advice, and that will be a big help to you.
I hope that helps.
If you need any more advice about the route, e-mail me and I will give you my best advice.