the TTB is a great independant suspension design for the street.
It can also be made to work well off road, but keeping it or not largely depends on what kind of off roading you want to do.
You would be surprised just how similar a EB and a Explorer are once the front end is removed, the frame a coil buckets are real similar, even the steering.If you do it right all an Explorer needs to mount up a D44 is the right axle and a trac bar mount, with a few tweaks to everything else. Solid axle conversions can be anywhere from $500 to $5000 depending on who does the work, the donor, and what you want to accomplish.
A search on this will yield enough info to read for days....
If I was to do it over again I would skip the TTB lifts and go solid straight away....