Robbie, I guess a good place to start is by asking,
are you tackling this yourself and are comfortable wiring everything up on your own?
How much are you likely to spend or want to spend ?
Those 2 things are likely to make a big difference to the options available to you.
For me a dc-dc charger with a solar input made sense and simplifies the wiring requirements by using one.
It will switch between charging the battery of the alternator when driving and turn to the solar when you're stopped.
If your confident in doing the job yourself, improvements can be made by having dedicated units for alternator charging and solar.
That will add a bit of cost and complexity. Not that hard though.
I've got a projecta dcdc/solar in the car and a supercheap dcdc and epever solar controller in the caravan.
Neither set up is at the top of the cost spectrum but both have worked well for me thus far.
For me I choose second hand solar panels from house installs. With the right solar controller benefits can be had from panels with higher voltage outputs and can be had dirt cheap.
I recently picked up 2 240w panels for 50 bucks each.
Batteries ? choose your poison based on price. I use giant batteries which are well priced and have mates who use them as well.
No failures yet.
re the fridge, as said once you have one you will never go back.
That said, I HIGHLY recommend against a 3 way fridge and would say ONLY buy a compressor fridge.
They have their place but in the back of a hot car isn't that place.
They only drop the temp around 20 degrees below ambient.
Run that in your car on a 40 degree day.... you get the point. Plus they will suck the life out of your battery.
My caravan one runs at 9amps constantly.
Whilst my solar set up on the van can run that easily during the day, add clouds or over night and your battery is flat or worse dead.
You don't need to spend a fortune on the fridge. Second hand can be a bargain and the cheaper end of the spectrum can be reliable as well.
If you have the bucks, an engel or waeco tend to be the picks.
I've got a giant (cheaper) and a waeco with friends who have ebay cheapies.
All are doing what they're meant to do.
I've got a series of videos on installing a dcdc and solar into my Paj if that helps.
I hope all this info that is coming at you is making sense.
cheers Brett