First, I appreciate your advice. Thanks for trying to help.
According to an online calculator, 40 psi will produce 5.3 volumes at 38 F and 60 psi will produce 7.3 vols. at 38 F. Unfortunately, these pressures will exceed the regular brown beer bottles I had planned to store the root beer in which I understand are good only to about 3.5 vols.
I spend the majority of my time at my lady friend's place, and she doesn't have room for a refrigerated keg. So, it's not a simple matter of dispensing from a picnic tap. I do have a few very old mostly-clear-glass swing-top bottles that were dirty and crusty when they were given to me. I could clean these, get new rubber gaskets, and try them.
One other concern I have is cleaning and sanitation. The ales I brew are always dosed with a new packet of dry yeast and presumably if a few bacteria survive my cleaning and sanitation efforts, they get outcompeted by the rapidly multiplying yeast that I pitched. Since my kegs are not equipped with spunding valves, I won't be adding yeast. I would appreciate any additional advice or suggestions. Thanks