They asked for and paid for 100 gallons of syrup. They received what is a standard 55 gal drum. This type of drum has been around for a very long time. And cannot contain 100 gallons of anything.
When they laid eyes on the barrel they asked what it weighed and were told three or four hundred pounds. They had also been told they were getting 100 gallons.
One gallon of maple syrup weighs 11 pounds. The drum they got was a 55 gallon drum so it would weigh 605 pounds. And if it somehow could hold the 100 gallons that drum would be over 1000 pounds. Even the 605 pounds would probably be more than four average middle-aged woman could deal with.
When they stop Christy says they are on Interstate five at mile marker 23. The problem is Interstate mile markers start with zero at the southern end or border, so mile marker 23 would be 23 miles north of the Mexican border, not south of the Canadian border. The second problem is that 23 miles south of the Canadian border on I-5 is in the town of Bellingham right in the middle of the exit loop.