Definitely solo. I don't want someone over at my house for 5 hours.
I like to start the boil on a weekend afternoon at three, add bittering hops, then go to the bar for a couple of pints. Come home 1.5 to 2 hours later, at later additions and finish up in 15 minutes. That has only bitten my a$$ a couple of times, when the propane runs out or if the wind comes up and snuffs out the flame.