I used a single axle 6 x 12 trailer to haul my RTV900 home, 12 hour drive.   Worked out fine.   I sure would not go smaller than that, and if possible get dual axle to increase your payload from 3500 to 7000.  I do not believe that is needed for the RTV's but if you want to haul heavier stuff it's good to have.
				
			
				
