Update by user Jan 16
Service techs finally got to diagnosing RV soft floor. Turns out there is NO water damage.
The Chassis is built by Lippert Industries, which makes most RV chassis. Floor is laminated styrofoam consisting of a THIN sheet of plywood, about 1 1/2" of styrofoam, and another thin laminate of plywood. Joists are 24" on center. Lippert says this floor is NOT designed for a wheelchair due to the concentration of weight on a very SMALL area.
Joists should have been 12" on center to support the weight. They had no idea Forest River was advertising this as wheelchair-accessible. Dealer will soon be installing additional cross-joists from Lippert. When they get to this point I will take pictures to show Forest River what the problem is with the "soft sagging" floor.
With no weight on the floor it sags more than 1/4" because the styrofoam in the 'sandwich floor' can not support the weight over a total of two square inches and has cracked/split, causing the sag. Hope Forest River will agree to do something besides "that's the way it's suppose to be." Probably should have info for them byt he end of the month.
Original review posted by user Aug 30, 2018
My wife and I have been camping/Rving since 1981 and owned four previous RVs [pop-up, travel trailer, two 5th wheels] with only minor issues that were always corrected. We took delivery of our first Forest River RV, a new 2013 V-Cross model 33-VFKS-HC wheelchair-accessible travel trailer, in November 2012.
 The floor felt "soft" but I was told that, per the factory, this was normal. Now six years later the soft floor is spongy. Walking across it you feel the 'bounce' as you walk. The floor is supported by 24" on-center joists.
Now instead of just being 'soft' there is more than a 1/4" sag between the joists with no weight on the floor and even more if you're in the RV. My wife uses a wheelchair due to a leg amputation and has felt the up-and-down movement of the floor as I walk on it since day one. Now she says it bounces! The dealer said it appears that the enclosed underbelly might not prevent water from getting the underside of the floor wet.
The estimated cost of repair is $10,000 or more. No other reasonably-priced RVs are made that are wheelchair-accessible so if we want to remain RVers it must be fixed.  In addition to the low-quality floor the heat vents can not support the weight of a wheelchair rolling over them. [They are not a heavy-duty 4x8" floor vent.] I must replace them about every two years as the 'fins' break.
 During the PDI the serviceman called the factory because an axle bolt was just an inch away from the waste water drain pipe. He was told this was the way it was designed and they've had no problems with it. In December 2017 there was a leak from both the gray and black water when draining the tanks. It turns out that the U-bolt put a nice hole in the drain pipe.
This 'normal' design resulted in a $753 repair! Whoever designed it this way shouldn't be designing plumbing layout.  The shower stall floor is not level. It is tilted to the outside wall so water does NOT go down the drain until it's about 1/2" deep.
I have to use my wash cloth to soak up the water and wring it out over the floor drain. [Maybe this is causing my warped floors?] This definitely isn't right.  I ordered a hitch from the factory with the RV and it was an E-2 hitch. [I had a 5th wheel before this.] The weight distribution / anti-sway bars are rated for 1,000 pounds.
How can they sell a hitch that is rated for basically the "dry" weight [7,515 pounds per the label]? 12% of the RV weight should be on the hitch so 12% of the dry weight is 901 pounds, within the hitch capacity. The GVWR is 11,185 pounds. My loaded weight is actually 10,650 pounds.
12% of 10,650 pounds is 1,278 pounds so my tongue weight of 1,250 pounds is right where it should be. That's 25% over the rated weight for the weight distribution / sway bars!! I'm surprised the bars didn't break. I'm glad the loaded RV doesn't weigh as much as the gross weight rating as that would be 1,342 pounds on the hitch.
 I've had to replace the relays-solenoids for the two slide-outs because they are mounted on the underside of the frame and are exposed to the elements as is the power tongue relay-solenoid. Being exposed means they get wet from rain water spray, rusting the contacts and solenoids. When they rust it greatly reduces the the flow of electricity so the slide-outs are stuck in the out or in position. This is a terrible design flaw.
 Upon delivery somehow the screen door hinges were bent out of shape. Rather than leave it with the dealer [we were leaving for Florida and when we returned we camped for the summer camping season] I returned it after the season for warranty repair. The entry door is 36" wide so a wheelchair can get through it. A month after ordering a door they received the door.
Opening the box showed it was only 30" wide! It was the wrong door. Another month later the next door was also 30" wife. Another month later the third door was 30" wide.
They were all ordered by phone and were specified as a 36" door. Another month and the 4th door was received. It was 36" wide. Then they discovered it was for the REAR door, not the front door.
They are different doors. Another phone call and, after five months from the original order, they finally sent the correct door. Then I'm told it was repaired AFTER the warranty expired and Forest River owuld not cover it!!! This was because they kept sending the WRONG DOOR!
My dealer wrote off his labor charges but I did have to pay for the door and shipping - over $1,000! I've left messages with the corporate office but have had no reply. V-Cross is no longer made so there's apparently no service department to repair it and no way to improve the quality of design or workmanship.
I know its out of warranty but I shouldn't have been having these problems from the beginning. Be careful of any Forest River product you buy.
Product or Service Mentioned: 2013 Forest River V Cross Platinum 33Vfks Hc Rv.
Reason of review: Bad quality.
Monetary Loss: $15000.
Preferred solution: Let the company propose a solution.
I liked: That the rv was wheelchair-accessible.
I didn't like: Quality of the materials and workmanship.