Absorption refrigerator cool down time

Camping in hot climates I never had problem with fridge being out of level.
My conclusion is that you want it leveled for starting and in case it would cycle off.
With my camping once I started fridge at level at home, it would never cycle off till I end camping trip. So even the pads where we were uncomfortable with sleeping, did not cost trouble with refrigerator.
I never used any fans on my fridges. Where they don't have high output, they do the work. As comparison, planning day trip today, I fired last night my house patio fridge. It is good fridge, but with 100F evening and 85F night, some water bottles in freezer are still liquid after 12 hr.
There is limit to everything.
Best you can do is freeze water bottles at night and put them on refrigerator door at day.

I was at the point of replacing my fridge with a compressor unit because I thought it wasn't working correctly. Turns out, I just wasn't smart on how to use it properly.

Fist, I've never really worried about leveling. If the camper is leveled enough to sleep, it has been good enough for the fridge. I have never noticed an issue in this regards to the point where I have to take extra care. That could just be my fridge isn't as picky as others so don't read into this one more than you have to.

Second, like others have suggested, precooling is important but to a point. There has to be thermal mass inside the fridge in order for the process to really start working well. You aren't cooling the air inside, your are cooling the food inside. Taking temperature readings in an empty fridge I don't think gives an accurate reflection of what is going on. My fridge won't even get into the 30s until I stock it up with food and leave it for a day.

Third point, my trick to quickly cool the fridge if necessary is to throw ice in the bottom bin and then place a small USB powered fan above the ice to blow on it. This helps to distribute the cold all around faster through convection. Only thing is to remove the ice before traveling or at least check to see if there is water that should be dumped. One could do the same with frozen containers but getting ice at a store is easier if your already on the road than frozen bottles of liquid.

Fourth and I think one of the most important tips is to keep your door stocked with aluminum can beverages of your choice. Once cooled down, they operate in the same concept as the cooling fins in the back of the fridge by radiation. I find having the extra aluminum present can efficiently radiate the cold stored in the liquid. It helps to keep the fridge cold when the door is opened frequently during meal prep.

Remember, you aren't cooling the air inside, you are cooling the food inside. It's why these fridges take so much more time to cool, it's by radiation, not convection. It is a slow process but also very efficient.

Lastly, if you can spare it, throw a bag of ice in the freezer on the bottom. This helps to add more thermal mass that keeps the temperature consistent during frequent use.

yes, it is slow! As above mentioned, I start the fridge day before on shore power. Departure day it is ready for cold food loading.

About 4 hour's to 40 degree's.

I did the test like 3 years ago and here are the results again.
Dometic 5 cu fridge about 16 yo at the time.

Refridgerator test
tm-amb-ins-fd/rf-flr/fr-fd/fr
12--80--80--80----80----80
1---87--84--78----64----80
2---90--86--78----35----71
3---91--88--74----23----55
4---94--90--69----17----46
5---94--90--68----13----36
6---92--90--64-----8----32
7---93--90--63-----9----32
8---89--89--57----12----36
10--79--85--55-----8----32 (froze)
6---64--74--47----10----32 ......day 2
9---76--75--45-----9----26 (thermostat switched off)
10--87--78--40-----0----15
12--94--87--42-----5----18
1---99--90--40-----2----13
4--103--96--39-----0-----6
5--104--94--40-----0-----3
6--100--96--40-----0-----1
8---93--95--40---(-5)----1
10--88--92--34---(-3)----4
turned off for the night/switched to propane
6---77--82--50----40----40..... day 3
7---77--82--50----30----36
9---86--85--48-----5----24
11--88--89--50-----2----11
12--92--92--55-----0----11
1---95--94--55-----0-----7
3--102--97--50---(-2)----2
4--103--98--50---(-2)----2
5--103--99--52---(-6)----1
7---99--99--50---(-5)----0

I simulated food with water bottles, so
fd is temperature of bottle inside the fridge.
Time is what clock show at given day.
ins=temp inside camper
fl = temp of freezer compartment floor

About 12 hours for my current fridge. Just like your's.

My test from several years ago showed a 100% duty cycle for 6 hours on electric, with an ambient temperature of 19 c (66 f)

Interesting, but sounds about right. We have a Dometic in our FW and although I haven't timed it, it seems to take that long to cool it down. Hence, we start it up the night before we're going to pack it for a trip.

I used to start mine early... have since moved to just turn it on, load it up with cold food and roll. By the time it gets warm it is already cold. Just don't stock it with a case of warm beer and you are fine.

Sounds about right on the timing. Quickest cool down is on electric.

As far as level, you only need to be within 3 degrees side-to-side and 6 degrees front to back per spec. For a normal mounted refrigerator with the back to a side wall, this equates to about 8" side to side and 8" front to back. Usually pretty easy to get within that.