If the frame members are further apart than 72 inches, we don't have a frame mounted hitch that would work.
If the fifth wheel has a 4 inch square steel bumper, a bumper mounted receiver like # E-100 would be a good choice. The hitch has a 350 lb tongue weight capacity which would be limited by the capacity of the bumper if its lower.
If you click the link, you can see a video featuring the bumper mount hitch I recommended. view full answer...
We don't have the specs for your specific trailer's wheel pilot hole. There are two common sizes for the just over 3 inch caps. We have the 3.19 inch option like # 319EZ and the 3.33 inch option like # AM90195.
The best way to know which you need is to use a digital caliper like # PTW80157. view full answer...
Based on the brackets you have near the suspension of your Open Range 3X 375RDS 5th wheel trailer your best option for a shock kit will be a Lippert kit that doesn't take up as much space as the Roadmaster kit you referenced.
For that you'd want the # LC281255 for if your trailer has 3,500 lb axles that are 2-3/8 inch in diameter or the part # LC281281 which fits axle diameters of 3 inch like what are found on 5,200 to 7,000 lb axles.
Also thanks for clarifying what the brown foam was.... view full answer...