Yes, the fridge could drain your starting battery.
Without looking up that *particular* model, i'd estimate 3.5 amps across an hour (hence 3.5Ah),
multiply by 24 for one day: 84 amp-hours consumption.
Your starter battery is 95 or 100 Ah, so it's now flat.
Without knowing oodles more about your situation (location, style of camping, etc etc), i would arm-wave (based upon my usage) 200 watts of solar panel, and at least a 100 amp-hour "house" battery. (me? i have only 67 Ah of house)((
my solar "system"))
But i've only had solar for the last year ... the previous 12 years were achieved by a mix of "plug the fridge into the Sprinter when the engine is running", plus occasional use of a plug-in-the-wall battery charger (for the house battery, altho it once saved my Sprinter bacon, too), plus seeking powered campgrounds (Washington and Oregon State Parks have that... California doesn't
)
Knowing your "reasonable" budget helps, too.
First Step: determine your *loads* .... convert them all to watt-hours to get the grand total per day.
Divide by 12 to get the equivalent 12v Amp Hours. ... that's what you'll need as "generation" per day, and you'll want a battery bank that can supply (your choice) XXX days between "sun" or "driving to recharge the battery"
(if you have an isolation relay to let the Sprinter charge the house ... you can pull at least 40 amps when the engine is running (in truth, depending upon your alternator size, maybe twice that).
Laptop power adapters can be quite power-hungry. 95 watts isn't uncommon ... so that's 95/12= 8 amp hours per hour of usage (with the laptop running ... simply "charging" is the same rate, but stops when filled).
--dick