Sorry but I don't have much experience with used Transit Connects, but I would shy away from one used for commercial use.
I gave serious consideration to getting a Transit Connect a couple of years ago. Lots of tradesmen had them, and I test drove both the panel van and the wagon version. Having owned 3 Econoline vans over the years, however, the TC was just too small IMO, especially for a combined use vehicle for 2 people.
The new Transit Connect (2014 and 2015 model years I believe), although better in certain ways, changed up the design again (dropping the roof quite a bit) and has even less headroom, so it also feels tight, again in my opinion.
I encourage you to test drive a short wheelbase (130"), low roof 2015 full-sized Transit Van, as the closest size-wise to the Transit Connect. My Wagon passenger model has fit the bill for me, and can tow a medium size trailer. In addition to my two threads linked below (XLT Wagon and Small Trailers), rmcnelly has a similar Wagon:
150 XLT 130" LR EcoBoost
XLT Wagon ordered
PS -- Cost will obviously be a consideration, and I think the main point I was trying to get across is that the Transit Connect may be too small for your two-person combined uses. Maybe a used Econoline, or other van would fit your needs better . . .