Help convince me to go BB in my Duster?

Just something like this? But instead of bolting I weld them?
http://www.summitracing.com/parts/dcc-4286868/overview/make/plymouth/model/duster

So assuming everything isn't rotted, if it's not going to be moving under the power (yet) I could wait on adding the subframe connectors? and other reinforcement? Or should I still have those in before I drop the block in?

I would bolt them in first, then weld. It just makes it easier. But yes, you could just weld them in.

I would do the connectors before I drop any engine into that car.