WORCESTER MOTOR HOMES

We are looking at buying an auto sleeper model "Worcester" on a Mercedes Chassis with rear wheel drive. Does anyone have any comments on their performance when going off road onto gravel/metal roads.? More importantly, we live in NZ and want to explore our bush and Nat. Parks. We don't see the point in having a motorhome just to stay on the tar seal. Any comments from other Kiwis with an Auto Sleeper of any model or any European models would be much appreciated. They certainly look nice and comfortable to spend time in, but they must be sturdy to handle tougher conditions.
Thanks.
Grey Nomad

PS. Would like to hear from any kiwis with a 'Worcester"