Anyone looking to retrofit a GMC Grand RV Motorhome, REE has the perfect solution for you, and then some:
REE’s P7-B box truck delivers 4,400-pound payload and up, 150-mile range, so plenty enough to move the GMC Motorhome fiberglass body once the cab has been removed.
Fully configurable, you can even opt for four wheel steering, and select the ideal wheelbase of track width:
ditto with the amount of battery cells
You could start with he box truck or you could simply opt fo the chassis version and build your RV from the ground up.