Oh, taxes are a big problem but you should learn a lot from your own experience. For the other, I would recommend reading about nitration of methyl benzoate at https://studyhippo.com/exp-3b-nitration-of-methyl-benzoate/ and similar to this. Some lessons are difficult but very important for your growth. No exception for taxes.
Martin nailed it. Hire a professional CPA. A good CPA will save you more money and headache’s than their fee is worth. Also, don’t stress taxes. Everything can be done retroactively. Fees and penalties are minor. The IRS can be a pain in the butt, but they can also be helpful.
At the last day of the trip, I have a ziplock for my hotel bill, the parking stub for the airport parking, and anything else I bought on the way home that was business related. Then I print out the email that shows the days and price of my airline flight.
That completes my little record-keeping system for fitness business travel.