A properly outfitted SRW can do the job. If I already owned the truck and felt I was was going to keep it a while, I would make the modifications required. Since the OP is starting fresh, I suggest going with a DRW unless there are enough restrictions to owning one in your area that he would prefer a SRW.
I ran 7000-8000 lbs on the rear axle of my modified SRW with no issues and only went to DRW due to expectations of 6000-8000 lbs of future payload.
Owning a MH requires you to vacation/live differently than when you have a tow vehicle. You either stay where you park for extended periods between breaking down camp or you have a supplemental vehicle to get around. Even with my DRW, we take seasonal vehicles with us to get around rather using the truck, but when we camp in inclimate weather the DRW is used to get around. I could not imagine breaking camp and touring local areas or small towns for the day in a 30+' MH.