NADA lists your 5th wheel under the manufacturer name [Hearland RVs].
The Big Country series had 9 models. Follow these steps, plus entering option accessories, to locate a blue book value.
We have used model [3691SK] for this example:
Go to [www.nadaguides.com]
Select = [RVS]
Select = [Travel Trailers / 5th Wheels]
Select Manufacturer = [Heartland RV]
Select Year =  < start here
Select Model = [3691SK / Big Country]
Enter Zip Code = 
Option = [Select]
[Get Base Pricing]
Suggested list price = $69872
Low retail = $29250
Average retail = $35250