It's definitely a Budd Conestoga, but Pima didn't open to the public until 1976, and was in a wide open field with a trailer for the office for years. Wikipedia does say a Conestoga used by Tucker Motor Company was abandoned at an airfield in Oakland, and Tucker folded around 1950. That might also be the one Pima has. Only 17 were built, and they had a reputation for crashing or burning.
Edit: Nope, the abandoned one in Oakland was scrapped according to research. Pima has a different one.
I found a site that lists what happened to each Conestoga
Budd RB-1 Conestoga
1 39292 NX41810 Later NC41810. To NSFC July 1945. Crashed in Fort Worth, Texas enroute from Augusta, Georgia to California, July 1945. Wreckage sold for $500 as a hamburger stand.
2 39293 NX37097 To NC37097 February 9, 1944. Damaged beyond repair in takeoff crash during NATC trials at Patuxent NAS April 13, 1944. One killed, 6 injured, one uninjured.
3 39294 NC45347 To NSFC July 1945. Due to fuel starvation in blizzard made a forced gear-up landing onto a golf course at Bluefield, West-Virgnia January 1, 1946, and subsequently written off.
4 39295 NC45348 To NSFC July 1945. Later sold to a user in Cuba, out of use by early 1947.
5 39296 – Made belly landing on wet grass August 7, 1944. Minor injuries, aircraft repaired. Made water landing in Chesapeake Bay when engines cut out August 30, 1944 and was written off.
6 39297 NC45349 To NSFC July 1945. To Shell Oil, Ecuador as HC-SBE August 1945. Damaged beyond repair in forced gear-up landing at Shell Mera , Ecuador, May 15, 1946. Remains used as local bar.
7 39298 NC41805 –
8 39299 NC45350 To NSFC July 1945. To Shell Oil, Ecuador as HC-SBF August 1945. Withdrawn from use due to wing fatigue problems July 23, 1946.
9 39300 NC45351 To NSFC July 1945. To Shell Oil, Ecuador as HC-SBG (or HC-SBH) August 1945. Withdrawn from use due to wing fatigue problems October 1946.
10 39301 NC45352 To NSFC July 1945. To Shell Oil, Ecuador as HC-SBH (or HC-SBG) August 1945. Withdrawn from use due to wing fatigue problems August 26, 1946.
11 39302 NC45353 To NSFC July 1945. Crashed near Alameda, New Mexico November 7, 1945. Pilot and copilot killed and flight mechanic severely injured.
12 39303 NC45354 To NSFC July 1945, renamed The Flying Tiger Line in 1947. Sold to Tucker Motor Company to transport their model 'Tucker 48' around the country for auto shows. Tucker went bankrupt April 19, 1949, plane was sold and used to fly shrimp in from Mexico. Last seen abandoned in 1980 at an airfield in Oakland, California, after repeated mechanical troubles.
13 39304 NC45355 To NSFC July 1945. To Expreso Aero Int of Havana, Cuba as CU-C413, then to Trans Air Hawaii, Ltd. as N5618V. May have not been taken up.
14 39305 NC45356 To NSFC July 1945, renamed The Flying Tiger Line in 1947. May have been the aircraft damaged on landing at Los Angeles IAP and donated to the airport fire department.
15 39306 NC45357 To NSFC July 1945. May have been the aircraft that crashed into a graveyard at Detroit, Michigan August 25, 1945.
16 39307 NC33308 To NSFC July 1945. Sold to Aerovisa Azteca. Flown in Mexico for many years as XB-DUZ. Being flown from California to Cuba in mid-1960s, it was abandoned on the Arizona/Mexico border and subsequently seized by US government for smuggling. Sat at Douglas, Arizona for many years before being sold at auction. Plane donated by the purchaser to Pima Air and Space Museum, Tucson, Arizona.