For less than $200 I switched all 4 of mine. Was going to replace the shoes and for a little more i switched to the never adjust with all new assemblies. Not sure how it could cost more than disc brakes. I reused my old drums. So far so good.
Sounds like a good trip other than your mileage. I'm usually flirting with 12 mpg with my diesel. Gas is ~15% more expensive than diesel in California and my mileage increased ~50%. And diesels have a higher trade in/resale value so everything should be considered. And now I have the diesel grin. Towing is much more enjoyable.