it seems to me, based on the position of the Horseshoe... that the street on the left side of the postcard would be 2nd Street, and the street at the top of the card would be 3rd Street, the street along the bottom would be Fremont. Right??

Just for the heck of it, I did some phone book browsing...must have been multiple entrances to the Simon Building...

October 1950:
Simon's Rainbow Quarries 111 N. 3rd, phone 83

August 1952:
Simon Bldg. 232 Fremont, phone 83
Simon's Rainbow Quarries 232 Fremont, phone 83
Melodie Lane 230 Fremont, phone 6771 (Yes, the address was listed as #230...not my typo!)

July 1956:
Simon Bldg. 111 N. 3rd, phone DUdley4-5783
Simon Rainbow Quarries 111 N. 3rd, phone DUdley4-5783
Melodie Lane Restaurant 234 Fremont, phone DUdley4-6771
Fremont Hotel 200 Fremont (didn't look at phone #)

July 1966:
Simon bldg. 111 N. 3rd, phone 384-5783
Melodie Lane Restaurant 234 Fremont, phone 384-6771
Fremont Hotel 200 Fremont, phone 385-3232
Internal Revenue Service 200 N Casino Center Bl., phone 382-0746

July 1969:
no listing for Simon Bldg.
Medodie Lane Restaurant 234 Fremont, phone 384-6771
Fremont Hotel 200 Fremont, phone 385-3232
Internal Revenue Service 300 Las Vegas Bl. South

July 1973:
no listing for Simon Bldg.
no listing for Melodie Lane
Internal Revenue Service 300 Las Vegas Bl, South
Fremont Hotel 200 Fremont

Jim, let me know if there's anything else I can do to help (or to mess you up! )