I see you found his Last Residence info on the Social Security record. The Social Sec. uses this field for their own purposes and it does NOT guarantee that was his last residence.
The State of Idaho won't release death info (unless family member) until 50 years after the death. Therefore, we'll use the Burley info because we don't have any other to find his obituary.
There is an obituary volunteer for Burley (Cassia) Co. at http://freepages.genealogy.rootsweb.ancestry.com/~obitl/voli...
Scroll down to Cassia Co and choose Lois.
If she can't find it, contact Janette but please DON'T ask both of them at the same time.
I didn't find any info For Myrtle.
Their burial information will be in their obituary or on their death certificates. Since you can't get a copy of their death certs, the following is a list of cemeteries in their county (I looked and they're not listed in FindAGrave).
Cassia County Historical Records, http://usgwarchives.org/id/cassis/history.html
Tombstone Transcription Project, www.usgwtombstones.org/idaho/cassia.html
Cassia County Cemeteries, http://usgwarchives.org/id/cassia/cemetery.html
Cassia County, Idaho Cemetery Records, www.accessgenealogy.com/cemetery/idaho/cassia_county.htm