The tow rating for the Lexus will tell you. I'm pretty sure it is 3500 lbs (check your owner manual), but that assumes only a 154 lb driver in the car and a tank of fuel. As a practical matter, the trailer should probably be no more than 3200 lbs loaded. If you don't know the loaded weight, assume the trailer GVWR is the weight.
Only the smallest Rpods, e.g. the R171 & R172, are in the 3200 lb GVWR range.
http://www.forestriverinc.com/nd/default22.asp?page=specs&nav=rec&choice=rpod
You would be far better off with a different tow vehicle. If its a Lexus, something like the larger 470 or 570 would do it handily. A GMC Acadia (or Buick Enclave) with tow package can handle 4500 lbs, which would be great for most any RPod. It is a nice, comfortable vehicle in the same class and price range as a Lexus RX series, but a bit larger and beefier.