95 33' land yacht towing?

Last year I bought a 33' 1995 Airstream land yacht. I have found out that it is built on a GMC C30 chassis, but I can not find anything about towing in any of the books. The owner I bought it from said he thought that it was about 1500 LBS and that if I wanted more the chassis would have to be modified. I have a 1999 VW Passat that I'm wanting to use a dolly to tow behind the RV. The other part to that is the Dolly is modified to hold my motorcycle (1983 Goldwing about 1000 LBS)



What I need to know is what is my towing limit right now?



How hard is it to increase the towing limit?



Is it something that I would be able to do or is it something that a professional needs to do?



Please I need help as getting ready for a long trip soon..