What kind of documentation is needed to show how much money I spend taking care of my parents mileage /wkly/300 + or - ?

Your safest bet is to check with a CPA. You can just keep a running account of your mileage, with the date, where you went and why, and your odometer reading. However, I strongly suggest a CPA for advice so you can rest assured you have the documentation you need for tax deductions.
Carol

Thank you! I only wish I had known this about 4 yrs ago!

As Carol states, IRS requires written documentation. Keep a written log that covers each and EVERY trip. The information you MUST have is date of EACH trip, purpose of the trip (if doctor visit, name of patient and facility), beginning and ending mileage if it's a single trip OR the mileage from the tax home to the destination if the trip has multiple stops. Sometimes I tell clients to figure the mileage using google and just use that for each trip. If you include personal stops during the trip, the odometer reading won't be accurate. And the IRS assumes that people will cover a route with both personal and deductible trips. Please remember that mileage rates for business, charitable and medical trips are calculated at different rates and that not all trips for caregiving are necessarily tax deductible. The documentation is not your only need but rather whether you are charging for trips, whether the individual is a dependent on you for taxes, and what the purpose of trips is. If you are being paid for caregiving services, it's a different set-up. This is a point where sitting down with a local CPA with your taxes and your parent's taxes is a good idea to make sure that you are handling the associated expenses correctly. Hang in there, Helen (pulling hair out this time of year)

Again, Thank you for your expeditious reply....very helpful!
Lin