I don't tow a vehicle, but I do tow a trailer with a Harley in it....never know it's back there except for the picture on the backup camera! There is plenty of power left in the V10, especially the newer models, to power the motorhome AND to pull a modest vehicle. As has been said, though, it can get quite loud when it downshifts to accommodate for the requirement of additional power. The V10 uses smaller pistons and higher RPMs to generate its power, but is a very reliable and powerful engine! On my 1999 model, I still get around 6-8mpg depending on how I drive and if I'm towing the trailer and running the genset.
For the noise level, you CAN add additional insulation to the doghouse to quiet it down some too!