...My wife and I (pre-marriage
) lived aboard our Vega 27 last year - not a huge stretch from the Columbia
24. Also met an older gentleman who had been living aboard
20 for quite some time (barely sitting headroom) - mind you, he was a ... short-statured fellow.
Heard stories too of a couple with two teenagers who lived aboard and cruised their Vega (27).
The question isn't really can you do it
; rather, as mentioned, it is do you really want to do it.
If you choose to enjoy it, it will be enjoyable. The previous posters are right: try it out for a month, and see how it goes - if you like it, do it; if you don't, don't do it.
...But it isn't even that black and white: if you love everything except the size of the boat, just get a bigger one. We just did - went from the Vega at 27' long overall with an 8' beam (same basic layout as the Columbia
, plus a hanging locker & heads between the main cabin
and the fo'c'stle) to a CSY 33
with an 11' beam, a real galley
, real saloon
and real 'bathroom', and now we have more than enough room for 2, and hopefully enough for 2 or 3 more 'small' people ... eventually.