Anyway, just my 2cents worth.
We never have 'crew'. WHen on passage, we do watch on and off. As such, we really singlehand whilst the others sleeps/ rests. I am trusting my son to do day watches but as a Dad, its difficult to sleep at night if he is on watch, unless its a milk run.
Having a stranger on board is difficult - their habits, moods, drugs or smoking etc. The skipper is responsible for life and limb etc and indiscretions of all crew. Its easier to not have them onboard. When I was a teenager, I crewed on many yachts/boats/ fishing trawlers. There can be lots of onboard dramas if people dont respect your personal space or if they think they know more than the skipper and dont have the ability to respectfully give advice etc etc etc.
As such, most people could singlehand or with 2 on board. If we can, then anyone can!! I went throught the phase of bringing everything back to the cockpit - but have reverted back to having all mainsail stuff at the mast.
Singlehanded - you do adjust to catnapping and can get 6-8 hours sleep in total. With crew you have to trust your life and your property to strangers. If it works - then great - go for it. We all need to build up experience somehow.