Purchasing a business

My wife and I have owned a food truck business for over ten years now. We have run this business in multiple locations, expanded, moved, changed the menu and even opened another cart with a completely different menu. We have done it with just the two of us at times and at other times we had as many as 10 employees. It's been successful, afforded us a comfortable life with a good amount of free time.

But now we both want to make more money and we are bored with our food cart business. Our current employees (a couple) are going to buy it and we are selling our house and moving back to a city we have done business in before and love.

So here is my problem. We have looked at brick and mortar businesses before and we are currently looking. Mostly we are shown profit loss statements, sometimes we see actual taxes. Often profit loss statements show terrible profits, have weird nonsense expenses or profits, have obvious math errors, or show something that runs opposite to what the owner is claiming. We have heard owners say that they make more money than their P/L or taxes claim but can't prove it because they were taking cash payments and not reporting them. Sometimes they say that the reason profits are low is because they had some onetime expense, overpaid rent, had a down turn or whatever. I always say show me your taxes and I'll believe it, but I worry even about those. It's just a photocopy of someone's taxes. How do I know they didn't edit it? How could I even find out if they did? I doubt anyone is going to let me log into their IRS account to verify.

So my question is to those that have bought established businesses. Specifically in the food and bar industry. How did you determine if the sellers claims were valid? Once you bought did sales and expenses match up to what they were claiming once you took over? Are there any scams, tricks or warning signs I should know about? Thanks in advance for any advice you can give!