Mobile/Independent shop operating costs?

So for the guys that are mobile/independent mechanics, I have a couple questions...

- Is it worth it or would you do something else if you could go back and start over?
- What percentage of the hourly rate that you charge do you pay yourself and put back into the business?
- What do you do for paperwork? Have an accountant handle it all or do it yourself?
- What are your operating costs just to exist (insurance, etc...)?

I have a few fleets and local farms that have voiced interest in this...

Mobile/Independent shop operating costs?

Mobile/Independent shop operating costs?