When I do vending, I cook the ribs a 1 - 2 days before and then cool them as fast as possible. They are cooked about 90% of the way by this time. I then will put them back on the smoker at the vending site. After about 45 to an hour, I finish and sauce them on my charcoal grill I have on my mobile smoker.
If the vending event is over 5 hours, I will cook half to three-quarters of the ribs like I said above and the rest at the event. The customers think that they are getting just cooked ribs when they see the smoker open and there are a combo of cooked and just cooking ribs on it.
I have never froze my ribs after cooking just because it is my preference. Try a test run of freezing them, then thawing and finishing them.
Chuck's Wagon BBQ
Meadow Creek CD-108
Small Drum Smokers