Face down on thick quilts after securing the mounting hardware often works, although sometimes I pull everything just in case.
Notable exception: RCA 630TS and similar models whose CRT is removed through the front. The CRT was shipped separately from the factory and installed in the cabinet by the dealer. The mounting inside the cabinet is
flimsy and can give way no matter how the set is positioned during transit. Removal takes only a couple of minutes, so there's no excuse for leaving the CRT in place unless you're robbing a house and hurrying to escape arrest.
I had an almost-mishap when bringing my RA-113 home. I removed the chassis, CRT, and yoke, but didn't think to check the safety glass and bezel, which a serviceman had reinstalled using a couple of licks of friction tape. I stowed the cabinet on its back, to avoid removing the knobs from the doors. A few minutes into the ride, I heard a BAM when the safety glass and bezel came loose and bounced off the floor. No harm done, but I felt like a dolt after taking so much care with the other bits.
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html