I would not do it. You will be losing 90% of the storage space you have had with the Class A MH. I would be looking at a B+ MH like the Roadtrek MH, or the Phoenix B+ on the Ford E-450 platform. With a MH you have all the basement storage space that is largely absent with a camper. By the time you get a DRW F-550 and a 11 foot camper with slideouts the cost will be more than one of these motorhomes.
The only advantage of a truck camper is being able to remove the camper and have the use of the pickup as a truck for hauling and being able to upgrade only the camper later.