Search Google for Tandem wheelchair. There are a few different ideas out there. That could solve the golfcart issue.
Another creative idea would be to see if someone could convert a conventional wheel chair into a side car for your electric wheel chair. If they did it right, they could maintain the collapsible part of it, so it would go through doorways and be used conventionally indoors.
The other issue would be that if you ever ran into a campground that would not accommodate a golfcart, they may need to be reminded of the ADA. Its not just a convenience. Some golf carts can be licensed as low speed electric cars, which means it would have the same rights as any other car.