I've been a FedEx Ground contractor for over 30 years and currently have 8 delivery vehicles servicing 30 zip codes in a 2700 square mile rural area in Tennessee.

Our business requires more cubic foot capacity and less weight capacity than what you are doing, but several other contractors I know are using the Promaster vans and are doing okay with them. The weak point seems to be transaxles and front wheel drive components. For you application you probably won't need to travel every stupid little gravel road / creek bed / cow path / ungraded 15% grade driveway - so you probably would have fewer problems with that.

For ergonomics you would probably benefit from the Promaster lower floor platform, batteries are really heavy. For my business they just don't have quite enough cubic feet of capacity.

Personally I have one Freightliner MT55 heavy step an, two GMC vans and seven GMC Savana 3500 box trucks. I pick them up used from UHaul with about 90-100K miles for under $10K, then hand them over to my guys who will abuse them mercilessly for another 150-200K miles with very few problems.

I'm a Mopar guy but business is business, and there's not a Dodge currently available that fits my application. Might work for yours if the transaxle stuff is up to the weight involved..