How many days at a time do you think you’ll be off grid without driving? I ask because if you think you’ll drive every day you may not need solar at all. I have a similar set up without solar (also a 2013 caravan!). For electrical I bought a 105Ah deep cycle marine matters installed it as an auxiliary battery and wired it to be charged by the engine with one of these [1] isolators. I have a Norcol - 30, which is a very similar fridge run off the aux battery. I have run it and basic lights for 2.5 days without moving the car. But every time I drive, it charges the battery! When I was on a three week national park trip I never went even below half battery. In fact I have never drained the battery in the two years I’ve been camping with it.

That being said, I didn’t run a laptop all day, just here and there for movies. But you can look up the wattage of your laptop and do some math to figure out what the power draw will be. All in all, if you plan to drive at least every other day I wouldn’t be surprised if the solar is unnecessary.

[1] WirthCo 1213.1241 20092 Battery Doctor 125 Amp/150 Amp Battery Isolator , Black https://www.amazon.com/dp/B0058SGDFK/ref=cm_sw_r_cp_api_i_5MXGQKBQMCDTEC43PAWV?_encoding=UTF8&psc=1

I got this one:

https://www.amazon.com/gp/product/B0058SGDFK/

I liked it because it is reversible in case I stupidly drain my starter batteries, I can use the AGM to charge them.