Do you have any documentation with the coach that provides specifications? What you really need is the GCWR (Gross Combined Weight Rating). Let's say your GCWR is 20,000# as an example. You then weigh your coach when it's fully loaded with everything you plan on taking, including driver and passengers. If your coach weighed 13,000#, then you'd be able to tow a 7,000# car or trailer as long as you don't exceed any of the other specs such as axle weights, payload weights, etc.
2016 Ford F350 Turbo Diesel SRW 4x4
2017 Grand Design Reflection 297RSTS
2013 Ford F350 Turbo Diesel SRW 4x4 (Destroyed by fire - 8/29/16)
2014 Grand Design Reflection 337RLS (Destroyed by fire - 8/29/16)