I'm not sure where in CT you are, but it won't really matter. The northeast just isn't a hotbed of expedited freight, since expedited freight is primarily manufacturing. There is some, to be sure, however. But most of it goes to the Midwest. I have had times when I've bounced back and forth between Jersey and Maryland up to CT and MASS.
That's what the Transit would be for, the local-ish up and down the eastern corridor, not long hauls with no place to sleep while loaded. I'd look for expediting companies that do such loads, and for air freight out of, first, mostly the CT airports, then Newark. Most of the loads I've picked up in New England have been in the triangle of Nashua, Worcester and Boston, although I have picked up several loads in the area between Stamford and Milford in CT.
The Isuzu is best suited to city delivery and more local runs, as well, so the same thing applies to that as the Transit.
The straight truck needs to be signed on with Panther, Load One, PTL, C&M, Road Runner, any of the larger well known carriers, and out on the road seeing the Midwest, Kansas City, Texas, the Grand Canyon, wherever the freight goes. I sure wouldn't want to deliver to places on Avenue of the Americas for a living in a straight truck. Or a Prius, for that matter.
As for selling the Transit and taking that kind of a hit, I wouldn't recommend it. There are already too many cargo vans out here in expediting in relation to the loads available, so upsizing the Transit really won't benefit you all that much. You can do the Transit over the road, as well, a lot of people do that in 2-sked Transits, but you just have to be careful in taking the loads longer than 600 or 700 miles with no place to take a nap while loaded. Sleep management and knowing your limitations will be critical if you wander too far from the east coast. But keeping loaded mileage down to where you can pickup and deliver and then go to sleep in there is the best way to deal with that.
If you can find a reliable driver for the Transit, $1000 to $1500 is doable, knowing that you'll need to split the revenue 60/40 with the driver, with whoever pays for fuel and tolls getting the 60%. The Freightliner can easily double that $1700 a week gross revenue with a husband and wife team in there, but $1700 is probably all you'll get as a solo. The Isuzu can easily do at least what the Transit can do, just in PITA air cargo.