If your actual weight will be 13,000 to 13,500 lbs, which seems reasonable given what you have said, then either the Ford 350 SRW with 6.2 and 4.30 or the Ram 3500 SRW with 6.4 and 4.10 gassers will work fine.
Will either of these gassers tow like a diesel? NO, but you are only towing 2,000 miles per year and commuting 13,000 miles per year. You live in MA (I lived there many years ago) which is cold. The gasser warms much faster and would be better on cold winter mornings when you can actually have the heater working even on the pretty short commutes.
The majority of diesels are fairly problem free. It is a gamble that if something major happens out of warranty on a diesel it can cost much more to fix than gas. If most of your commuting is 10 mile plus trips, then the diesel sounds good. If most of your commuting is 1 to 2 mile trips and it never goes more than 20 miles except for a few times a year, then I personally would not buy a diesel. I love my Cummins when pulling, but some applications are just more suited to gas.
Hope this helps some. Keith
