How many miles?

A lot depends upon how hot it actually got.  Since the paint survived well,
it would suggest
that the metal parts, at least, may not have been damaged.  If so, then the
engine is probably
rebuildable.

The soft parts bother me though.  Even if the heat didnt apparently scorch
them, they may not
work as they should and may crumble sooner than they would have normally.
The fuel injection
may take a bit of doing to get it back like new.

If I bought it back, I wouldn't offer too much, figuring you are going to
have to rebuild everything.
Is it worth it?

i would give it better than 50% evaluation. of the many burn jobs ive
done thru the years ive never replaced the engine/trans assy. had one
that got so hot the metal valve covers melted into the rocker train. on a
bet with tech next stall over i/we installed new rocker arms, nuts, valve  
covers, dist, throttle body, plugs, all sec. ign. wires, crank seals,
timing cover gask,water pump, front and rear seals in trans, used torque
conv., modulator and pan gask on trans. dropped it into simular junker on
lot and drove it 2yrs. for parts runner. no leaks, no probs.....if this
had been a retail job for customer it would have not been cost feasible
but with free labor and reasonable parts prices we didnt spend much.
didnt have the heart to collect the $100 tho. he got so involved with
project i think he did most of the work. it was a great way to make a
good friendship thats lasted over 20yrs. and with mechanics its difficult
to build strong positive relationships with each other because we all
know WE are the smartist one in the room ;-)...good luck, kjun

Thanks to all for the replies, I have been out of town for a while and
didn't get a chance to read the NGs until now. The engine had ~10K mi on
it. The truck's in a tow yard 250 mi away (the burn happened on a
camping trip). If I can buy it back from the ins co for a good price,
I'll drive up with a trailer and pull the engine, trans & xfer case.

-- cb