JC & Dennis: thanks for the valuable input you gave. Sounds like, coming from being a trad keyboard player that the best RH accord type option for me is 'keyboard style' vs 'buttons' giving better opportunity on focus on learing the button (chord progression changes) by touch, namely the most common: IV-V7-I, and II-V7-I in the most common keys, and hitting the associated bass notes by touch, no peeking.

The reason I'm exploring the prospect of an accordion is because it's the only 'keyboard type' instrument I know of that doesn't require electrical power, and supports accomp and playing RH lead melody & fills while singing, as it appears to be the direct 'one man band' acoustic descendant of the arranger keyboard.

To afford portability, I prefer something relatively compact & lightweight. Which 'piano key style' accords brand & models meet this criteria? Thanks to all for any additional information & advice.

Scott