AWD rigs gain nothing by pulling the driveshaft. Personally, I think all it does is lighten up the steering.
I have to tell you that about the last thing I would do in sending
on a 4K roadtrip is pull part of the driveline where it is not available if for some reason she needs it.
There is nothing you can do to gain 2 mpg on an 80 that does not have a current service issue. If pulling the driveshaft saved 10 gallons of gas on that entire trip I would be surprised.
Take the driveshaft to a good drlveline shop and get it fixed. If it isn't the driveshaft, leave it alone.