planning to purchase a business (things to watch out for)

I am planning to purchase a business around a 1 mil range with a partner.
Only purchasing business not the property.

This is my first time. What are the things I should watch out for?
The partner is someone I do trust (related to me).

The things I have been looking at:
- how long has the business been operational
- records for last 5 or so years
- inspection during business hours of customers/purchases etc.
- any bankruptcy filed (Not that it matters as my own corp will take over the lease.)

For privacy reason I don't want to say what but it is food related.
Hence I am looking at if there are any health inspection complaints by the city.

Some of the sellers have mentioned that a part of the income is cash so they don't keep a record of it.
Although it does set off a red flag but I know this to be true of many businesses.

Another question is around bank financing.
Between myself and my partner, we have about $400k, how difficult would it be to get around $600k from the bank and what type of term and interest are we looking at?
Also how difficult is the process to secure this type of lending from the bank?


Thanks