I'm in central Florida and have a stucco over frame house, monolithic
slab, drywall interior walls. I saw some swarms of carpenter ants
around a bedroom window a while back. Pulling away the drywall, I
found carpenter ant damage as well as what to me look like some
non-active termite mud tubes running up either side of one of the
2x4's.

Since then I've knocked away some of the stucco along one outside wall
at a different location (the garage) at ground level exposing the edge
of the slab and found a few mud tubes, then looked inside the wall
with a boroscope. I found more mube tubes along a couple of the 2x4's
running along the point where they contact the presswood under the
stucco.

I knocked away some of the drywall to get a closer look. I have no
idea how old these mud tubes are, some extend higher than the area
where I've opened the drywall, some just stop. The 2x4's I've checked
so far seem solid when jabbing at them with a screwdriver. I don't see
any of the classic "swiss cheese" bored into look that I've seen on
some damaged wood. If the termites have done significant damage to the
2x4's, should it be obviously detectable from the outside? How do they
operate, do they munch as they go or do they build a tube to a
particular destination? As I check other walls with the boroscope, if
I don't see mud tubes along the 2x4's can I assume they haven't gotten
in at those points? I also plan to look up in the attic (or what
passes for one here in Florida) to see what I can see there.

A local do-it-yourself pest control place told me that if you do a
trench and fill termite treatment around the perimeter of the house,
cutting the termites inside the house off from the outside, any
termites inside will die out. Does this sound correct?

Thanks for all input.