Continuity mistake: When the Gornickes catch up with the RV, its shadow is cast to its right, but after Cassie tackles Carl to the ground, there's an exterior shot of the RV and bus as they both cast long shadows to their left. This drastic change in shadows continues in following shots. (00:57:00)
Continuity mistake: When the thoughtful gentleman offers Cassie the 'vegetarian' organ stew things on the table disappear, reappear and change between shots, such as Earl's plate, the flowers, etc. (More visible on fullscreen DVD.) (00:32:50)
Continuity mistake: After Travis hoses the turd off Bob, when Billy remarks that 'Ernest Goes to Jail' is funny, the boy's left front tooth (viewer's right) is fully grown in; however, that evening, after dinner, Billy's tooth is barely halfway grown in. (00:28:55 - 00:37:00)
Continuity mistake: After Jamie pinches Carl's ear because he spills their destination, when Mary Jo walks toward the Munros, Billy's back faces the camera as he stands on the ground, away from the bus. However, in the next shot Billy faces the camera as he stands on the stool while leaning on the bus. (00:35:10)
Continuity mistake: When Bob is chasing the Gornickes on the bicycle, the bus turns right onto the highway. In the next shot, it is turning left. (01:12:00)
Continuity mistake: In the RV, when Bob turns around to glance at Cassie after the dishes fall on her, in the first shot his arm rest is up (look beside his right shoulder) as he faces her, but when he says, "My bad," the arm rest is down. (00:15:30)
Continuity mistake: When the Munros first hitch a ride with the Gornickes, after Bob takes off on the bicycle, as Cassie questions Earl the calculator repeatedly disappears, then reappears, and the books, etc change between shots. (01:18:55)
Continuity mistake: When Gary and Larry catch up with Bob, the trees and snow surrounding the two cars differ after the RV destroys the vehicles; also, note the tree tops. (01:31:50)
Continuity mistake: When Bob is hanging onto the RV's wiper blades, as it nears the campsite, in the last close-up his shirt is completely dry, but in the first shot just as he is thrown backwards, suddenly there are numerous sweat stains on his shirt. (01:12:30)
Continuity mistake: At the very end when the Munroe family gets stopped by the police, they walk directly behind the RV. A moment later when the RV rolls down the hill (and runs over the police car) it is facing toward them. For it to do this it would have to run over them.
Continuity mistake: In the RV, Jamie puts stacks of dishes away in the overhead cabinet - second from right, when Cassie moves Carl off the couch. When Bob makes the sharp right turn, the dishes pour out of the overhead cabinets, but the ones that come out of the second cabinet are not the same dishes that Jamie put away. (00:12:20 - 00:15:00)
Continuity mistake: When Bob speaks to his coworkers at his office, Bob says, "Bring jewelry," and his glass is nearly empty, but a couple of shots later, as he still sips his straw, the glass actually has more liquid now. (Difference only visible on fullscreen DVD.) (00:08:45)
Continuity mistake: When Earl gives Cassie the list of places that sell organic health food, in the close-up she holds the papers with her right hand at the top and left hand at the bottom. However, in the next shot it's the opposite way, her right hand is at the bottom and left at the top. (00:44:05)
Continuity mistake: Just forward of the right rear wheelwell, a small dent disappears and reappears throughout the movie.
Continuity mistake: When they arrive at a campsite to take in the view of the lake that Bob saw with his family as a kid they leave the door to the RV open with the stairs down. After some dialogue the RV rolls into the lake with the stairs up and the door closed.
Continuity mistake: When Jamie and Bob are sleeping in their bed, the things from the bedside table have been changed.
Continuity mistake: After Bob comes home with the RV, when he and Jamie walk into the kitchen there is a butcher block cutting board laden with items, at the edge of the counter. However, when they speak beside that island counter the cutting board is gone. (Even more noticeable on fullscreen DVD.) (00:10:20)
Continuity mistake: When the Munros pick up Gretchen at her house, many shadows are cast on the lawn. Later, when they drop her off, the shadows are identical - they have not changed a bit. (00:03:20 - 00:05:25)
Continuity mistake: When bike riding Bob chases down the Gornicke bus, in the front shots their shadows jump from their right to left between shots, while driving in a straight line. (01:22:15)
Continuity mistake: After being snubbed by Carl and Cassie, when Bob walks into the kitchen as Jamie speaks to her sister, the chopper jumps to the other side of the butcher block cutting board, and the chair beside the laptop turns by itself, etc. in following shots. (00:06:30)
Answer: In the world of "make believe", they used "movie magic" to zap the RV out of the water and on to dry land - with no mechanical issues resulting from being submerged. In the real world, someone called a tow truck - perhaps AAA - and the RV was pulled out of the water and it suffered water damage and needed some repairs. This movie was presented as being "real life." Bob left on a bicycle to "try to find help." Near the end of the movie, Carl said that the RV "spent two days under water and they had to fish it out." He didn't say who "they" were. A fishing pole would not be strong enough to reel in a large RV, so I think it is safe to conclude that a tow truck was used to pull the RV out of the lake.
KeyZOid
It should be noted that "fish it out" is a common phrase to mean pull or take out, especially after searching. When people use the term, they're never taking about using a fishing pole. But often when people post questions like this, they're asking for an in-film explanation in case they missed (or didn't understand) something. If no in-film explanation was given, a reasonable speculation can be given. You don't need to remind people the movie is a movie. If the in/film explanation is uncharacteristic to real life, then one can point out that in real life it wouldn't happen that way.
Bishop73
It was meant to be ironic.
KeyZOid
There was no irony, but this isn't the forum for irony anyways.
Bishop73
I guess I failed miserably... but wasn't the original question rhetorical?
KeyZOid