So having been lucky enough to find this black 301 shortbed at a yard sale for $10 - with another $20 to replace foot controller - I needed only to install it in a Singer cabinet to have the perfect sewing experience.
Cradle Adapter for installing 301 shortbed
The 301 shortbed is unique in that it can be installed in a cabinet like any other full sized vintage Singer but then this machine just pops out of its cabinet and goes along to wherever you need to take it, carried by the clever handle right on top the machine (a stand alone feature, not seen on any other vintage Singer, not even the Featherweight.) The thing that makes this possible is the "cradle adapter" into which the machine fits in place in the cabinet. The lever on the left releases the machine when you want to remove it. VERY, VERY COOL!
But all Singer cabinets are not exactly alike. There is one crucial element that determines which type of machine can be installed in the cabinet. Most of the mid-century cabinets are configured to hold machines like the 15-91, 201, 66, etc. When the machine is in place, it rests on a lip protruding on a hinged panel that folds down. Like this:
Installing the 301 requires brackets to hold the cradle adapter on this panel and it must be flush in order for the machine to fit. Like this:
I was frustrated to realize that my 301 could not fit into either of the two cabinets I already have, but I later picked one up at another estate sale - once I knew what to look for.
UPDATE: I later upgraded to the beautiful Singer #42 cabinet which I like even better. (This style cabinet comes in BOTH configurations as shown above, so you have to look closely to see which machines it will take.)