Completely Feel for you here, I have ran business with limited staff and about to do the same again, we me and my wife running a new lot, wile I also try keep the garage running with the skeleton staff we now have.
Yes it can be done, but only short term if you have a lot going on. You need to get things moving quickly and be able to afford more help (staff) when possible. I think it is a lot easier to run 1 business on your own if you have good people offering services. Valet company, Mechanic, Paint Main etc.
Sometimes in business you can get that key staff member who can take so much crap of your hands and free you up to do the things you should be doing, Managing your business.
My wife had our baby Daughter on the Sunday and was back in work Tuesday night running the office for a big sale we had on when we ran a auction business. That's how bad it got a one point.