My $22000 per year on trucks was a low conservative amount, and didn't include maintenance- just depreciation based on someone's estimate of 60 miles per day. Figure depreciation of about 15 year max in real life while being driven hard. A lot less for box trucks/vans. So a mixed fleet might have an average life of 12 years MAX. A mixed fleet might average $60k in vehicle cost. Over 12 years, that comes out to more like $5000 average per vehicle.
And my 8 drivers per 5 routes was a little high, except for the one time it isn't. I think that if you can staff with people who WANT to work less than 40 hours, maybe half your drivers, you have a lot of flexibility when you do have a staffing issue. You can have them work a little extra each if you end up short, and during peak. I don't know what a manager for 5-10 routes would make, but as soon as your manager has the title of manager, he/she wil be looking for a real job with benefits with a decent resume.
And you will be like other owners very fast- just dreading the day when the inevitable problems do come up. You might have a mgr quit and a couple drivers absent at the same time, a driver will get 'FED-UP' about 10AM and just walk off the job maybe leaving the truck unlocked in the middle of downtown.
So many things can go wrong that putting your own money up is in my opinion just stupid. If you could get the previous owner to finance 80% for the first couple years, with a balloon due then, you should by then know if it is worth risking your nest egg. You will have some carrying costs, but that is cheap insurance. Too many risks to make a giant leap like you are considering. Even if you can find a lender, worst case is bankruptcy, and you can protect your cash. Waking up every day dreading that something is going to go wrong, even if not today, is no way to live.